library 
 
 OF THE 
 
 University of North Carolina. 
 
 THE WOOD COLLECTION, 
 
 Presented by Thos. I\ Wood, M. 1). 
 
 Ar ' C0V ® $HJ3I, F 
 
 DIVISION OF HE M.TH ' HV.rS UBRAR? 
 

 
AN 
 
 INQUIR Y, 
 
 &c. &c. 
 
 
 V 
 
AN 
 
 ' U/ 
 
 IJVQ UIR Y 
 
 x 
 
 INTO 
 
 THE CAUSES AND EFFECTS 
 
 OF 
 
 THE VARIOLiE VACCINAE, 
 
 A DISEASE 
 
 DISCOVERED IN SOME OF THE WESTERN COUNTIES OF ENGLAND. 
 
 PARTICULARLY 
 
 GLOUCESTERSHIRE, 
 
 AND KNOWN BY THE NAME OF 
 
 THE COW POX. 
 
 / 
 
 BY EDWARD JENNER, M. D. F. R. S. Ac. 
 
 -- GUID NOBIS CERTIUS IPSIS 
 
 SENSIBUS ESSE POTEST, GUO VERA. AC FALSA NOTEMUS. 
 
 LUCRETIUS. 
 
 BfeifflfcMSWWF 
 
 SECOND EDITION. 
 
 / 
 
 Honfcon: 
 
 PRINTED, FOR THE AUTHOR, 
 
 BY SAMPSON LOW, N°. 7 , BERWICK STREET, SOHO : 
 
 AND SOLD BY LAW, AVE-MARIA LANE; AND MURRAY AND HIGHLEY, FLEET STREET 
 

 J 
 
 
 1. 9^ t 
 
 W . v 
 
 
 i , * • •. 
 
 Digitized by the Internet Archive 
 in 2020 with funding from 
 University of North Carolina at Chapef Hill 
 
 https://archive.org/details/inquiryintocauseOOjenn 
 
TO THE KING. 
 
 SIR, 
 
 When i firft addrefled the 
 
 Public on a Phyfiological fubjecft which I con¬ 
 ceived to be of the utmoft importance to the 
 future welfare of the human race, I could not 
 prcfuinc; in that early ft age of the inveftigatiory 
 
 to 
 
 11 
 JL JSL 
 
 /n rr? 
 J 
 
 'I- U 
 
 
[ vi ] 
 
 to lay the refult of my Inquiries at your 
 Majefty’s feet. 
 
 ' >'i *y/-i 1 i 
 
 Subfequent experiments, militated not only 
 by myfelf, but by men of the firft rank in the 
 medical profeffion, have now confirmed the 
 truth of the theory which I firft made known 
 to the world. 
 
 i 
 
 Highly honoured by the permiffion to dedi¬ 
 cate the refult of my Inquiries to your Majcfty, 
 
 1 am imboldened to folicit your gracious pa¬ 
 tronage of a difcovery which reafon fully 
 authorizes me to fuppofe will prove peculiarly 
 beneficial to the prefervation of the lives of 
 
 t 
 
 mankind. 
 
 rp 
 
 Jo 
 
\ 
 
 [ vii ] 
 
 To a Monarch no lefs juftly than empha¬ 
 tically ftyled the Father of his People, this 
 Treatife is infcribed with perfeft propriety ; 
 for, confpicuous as your Majefty’s patronage 
 has been of Arts, of Sciences, and of Com¬ 
 merce, yet the moft diftinguilhed feature of 
 your charafter is your paternal care for the 
 deareft interefts of humanity. 
 
 X am, Sir, 
 
 SIR, 
 
 With tiie moll profound refpeft, 
 
 Your Majefty’s moft devoted 
 
 Subjeft and fervant, 
 
 EDWARD JENNER. 
 
 Berkeley, Gloucefterfhire, 
 
 Dec. 20th, 1799- 
 

 
 
 
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AN 
 
 INQUIRY, 
 
 &C . &C. 
 
 The deviation of Man from the ftate in which 
 he was originally placed by Nature feems to have 
 proved to him a prolific fource of Difeafes. From 
 the love of fplendour, from the indulgences of 
 luxury, and from his fondnefs for amufement, he 
 has familiarifed himfelf with a great number of 
 animals, which may not originally have been in¬ 
 tended for his affociates. 
 
 B 
 
 The 
 
\ 
 
 ■ C 2 ] 
 
 The Wolf, difarmed of ferocity, is now pillow¬ 
 ed in the lady’s lap*. The Cat, the little Tyger 
 of our ifland, whofe natural home is the foreft, is 
 equally domefticated and careffed. The Cow, 
 the Hog, the Sheep, and the Horfe, are all, for a 
 variety of purpofes, brought under his care and 
 dominion. 
 
 There is a difeafe to which the Horfe, from his 
 ftate of domeftication, is frequently fubjeft. The 
 Farriers have termed it the Greafe. It is an in¬ 
 flammation and fwelling in the heel, from which 
 iflues matter poflefling properties of a very pecu¬ 
 liar kind, which feems capable of generating a 
 difeafe in the Human Body (after it has under¬ 
 gone the modification I fhall prefently fpeak of), 
 which bears fo ftrong a refemblance to the Small 
 
 * The late Mr. John Hunter proved, by experiments, that the Dog is the 
 Wolf in a degenerated ftate. 
 
 Pox, 
 
Pox, that I think it highly probable it may be 
 the fource of that difeafe. 
 
 In this Dairy Country a great number of Cows 
 are kept, and the office of milking is performed 
 indifcriminately by Men and Maid Servants. One 
 of the former having been appointed to apply 
 dreffings to the heels of a Horfe affefted with the 
 Greafe , and not paying due attention to cleanli- 
 nefs, incautioufly bears his part in milking the 
 Cows, with feme particles of the infeftious matter 
 adhering to his fingers. When this is the cafe, 
 it commonly happens that a difeafe is communi¬ 
 cated to the Co\Vs, and from the Cows to the 
 Dairy-maids, which fpreads through the farm 
 until moft of the cattle and domeftics feel its un~ 
 pleafant confequences. This difeale has obtained 
 the name of the Cozu Pox . It appears on the 
 
 * f ■. _ , •, * . • ■ 
 
 nipples of the Cows in the form of irregular 
 
 B 2 puftules. 
 
V 
 
 [ 4 ] 
 
 puftules. At their firft appearance they are com¬ 
 monly of a palifh blue, or rather of a colour 
 fomewhat approaching to livid, and are furround- 
 ed by an inflammation. Thefe puftules, unlefs a 
 timely remedy be applied, frequently degenerate 
 into phagedenic ulcers, which prove extremely 
 troublefome*. The animals become indifpofed, 
 and the fecretion of milk is much leffened. In- 
 
 ' . , \ ' • ‘ . ' *v; 
 
 flamed fpots now begin to appear on different 
 parts of the hands of the domeftics employed in 
 
 milking, and fometimes on the wrifts, which 
 
 » ' . 
 
 quickly run on to fuppuration, firft affuming the 
 appearance of the fmall veflcations produced by a 
 burn. Moft commonly they appear about the 
 joints of the fingers, and at their extremities; but 
 whatever parts are affefted, if the fltuation will 
 
 * They who attend lick cattle in this country find a fpeedy remedy for flop¬ 
 ping the progrefs of this complaint in thofe applications which adl chemically 
 upon the morbid matter, fuch as the folutions of the Vitriolum Zinci, the 
 Vitriolum Cupri, &c. 
 
 i 
 
 admit, 
 
 i 
 
[ 5 ] 
 
 I , 
 
 admit, thefe faperficial fuppurations put on a 
 * 
 
 circular form, with their edges more elevated 
 than their centre, and of a colour diftantly ap¬ 
 proaching to blue. Abforption takes place, and 
 tumours appear in each axilla. The fyftem be¬ 
 comes affected, the pulfe is quickened; fhiver- 
 ings, fucceeded by heat, general laffitude and 
 pains about the loins and limbs, with vomiting, 
 come on. The head is painful, and the patient 
 is now and then even affefted with delirium*. 
 Thefe fymptoms, varying in their degrees of vio¬ 
 lence, generally continue from one day to three 
 or four, leaving ulcerated fores about the hands, 
 which, from the fenfibility of the parts, are very 
 troublefome, and commonly heal {lowly, fre¬ 
 quently becoming phagedenic, like thofe from 
 
 * It -will appear in the fequel that thefe fymptoms arife principally from the 
 irritation of the fores, and not from the primary a£lion of the vaccine virus upon 
 the Conftitution. 
 
 whence 
 
I 6 ] 
 
 whence they iprung. The lips, noftrils, eyelids, 
 and other parts of the body, are fometimes affe£l- 
 ed with fores; but thefe evidently arife from their 
 being heedlefsly rubbed or fcratched with the 
 patient’s infefled fingers. No eruptions on the 
 Ikin have followed the decline of the feverifh 
 fymptoms in any inftance that has come under 
 my infpeftion, one only excepted, and in this 
 cafe a very few appeared on the arms: they were 
 very minute, of a vivid red colour, and foon died 
 away without advancing to maturation; fo that I 
 cannot determine whether they had any connec¬ 
 tion with the preceding fymptoms. 
 
 Thus the difeafe makes its progrefs from the 
 Horfe (as I conceive) to the nipple of the Cow, 
 and from the Cow to the Human Subje£t. 
 
 Morbid matter of various kinds, when abforbed 
 i into 
 
 / 
 
 « 
 
into the fyftem, may produce effe£ts in fome 
 degree fimilar; but what renders the Cow Pox 
 virus fo extremely fingular, is, that the perfon 
 who has been thus affefted is for ever after fecure 
 from the infeflion of the Small Pox; neither ex- 
 pofure to the variolous effluvia, nor the infertiom 
 of the matter into the lkin, producing this dif- 
 temper. 
 
 i 
 
 In fupport of fo extraordinary a faft, I {hall 
 lay before my Reader a great number of inftances: 
 but firft it is neceffary to obferve, that puf- 
 tulous fores frequently appear fpontaneoufly on 
 the nipples of the Cows, and inftances have oc¬ 
 curred, though very rarely, of the hands of the 
 fervants employed in milking being affe&ed with 
 fores in confequence, and even of their feeling 
 an indifpofition from abforption. Thefe puftules 
 are of a much milder nature than thofe which 
 
 arife 
 
[ 8 ] 
 
 Tirife from that contagion which conftitutes the 
 true Cow Pox. They are always free from the 
 bluifh or livid tint fo confpicuous in the puftules 
 in that difeafe. No eryfipelas attends them, nor 
 do they Ihew any phagedenic difpofition as- in the 
 other cafe, but quickly terminate in a fcab with¬ 
 out creating any apparent diforder in the Cow. 
 This complaint appears at various feafons of the 
 year, but moft commonly in the fpring, when the' 
 Cows are firft taken from their winter food and 
 fed with grafs. It is very apt to appear alfo when 
 they are fuckling their young. But this difeafe 
 is not confidered as fimilar in any refpeft to that 
 of which I am treating, as it is incapable of pro¬ 
 ducing any fpecific effects on the human Con- 
 ftitution. However, it is of the greateft confe- 
 quence to point it out here, left the want of dis¬ 
 crimination fhould occafion an idea of fecurity 
 from the infe£tion of the Small Pox, which might 
 prove delufive. 
 
 / 
 
 CASE 
 
[ 9 ] 
 
 / 
 
 JOSEPH MERRET, now an Under Gardener to the Earl of 
 Berkeley, lived as a Servant with a Farmer near this place in the 
 year 1770, and occasionally affifted in milking his mafter’s 
 cows. Several horfes belonging to the farm began to have 
 fore heels, which Merret frequently attended. The cows foon 
 became affedted with the Cow Pox, and foon after feveral fores 
 appeared on his hands. Swellings and fliffnefs in each axilla 
 followed, and he was fo much indifpofed for feveral days as to 
 be incapable of purfuing his ordinary employment. Previoufly 
 to the appearance of the diftemper among the cows there was no 
 frefh cow brought into the farm, nor any fervant employed who 
 was affedted with the Cow Pox. 
 
 In April, 1795, a general inoculation taking place here, 
 Merret was inoculated with his family; fo that a period of 
 twenty-five years had elapfed from his having the Cow Pox 
 to this time. However, though the variolous matter was re- 
 
 C • \ peatedly 
 
 \ 
 
[ 10 ] 
 
 peatedly inferted into his arm, I found it impracticable to infeCt 
 him with itj an efflorefcence only, taking on an eryfipelatous 
 look about the centre, appearing on the Ikin near the punCtured 
 parts. During the whole time that his family had the Small 
 Pox, one of whom had it very full, he remained in the houfe 
 with them, but received no injury from expofure to the con¬ 
 tagion. 
 
 It is neceffary to obferve, that the utmoft care was taken to 
 afcertain, with the mod; fcrupulous precifion, that no one whofe 
 cafe is here adduced had gone through the Small Pox previous 
 to thefe attempts to produce that difeafe. 
 
 Had thefe experiments been conduced in a large city, or in 
 a populous neighbourhood, fome doubts might have been en¬ 
 tertained ; but here, w 7 here population is thin, and where fuch 
 an event as a perfon’s having had the Small Pox is always 
 faithfully recorded, no ri(k of inaccuracy in this particular can 
 arife. 
 
 CASE 
 
t 11 ] 
 
 CASE IE 
 
 SARAH PORTL 0 CK, of this place, was infected with 
 the Cow Pox, when a Servant at a Farmer’s in the neighbour¬ 
 hood, twenty-feven years ago*. 
 
 0 
 
 In the year 1792, conceiving herfelf, from this circumftance, 
 fecure from the infeHion of the Small Pox, fhe nurfed one of 
 her own children who had accidentally caught the difeafe, but 
 no indifpofition enfued.—-During the time fhe remained in 
 the infedled room, variolous matter was inferted into both 
 her arms, but without any further effedl than ip the preceding 
 cafe. 
 
 * I have purpofely feledted feveral cafes in which the difeafe had appeared 
 at a very difcant period previous to the experiments made with variolous 
 matter, to {hew that the change produced in the conftitution is not affe&ed by 
 time. 
 
 C 2 
 
 CASE 
 
[ 12 3 
 
 CASE III, 
 
 JOHN PHILLIPS, a Tradefman of this town, had the 
 Cow Pox at fo early a period as nine years of age. At the age 
 of fixtv-two I inoculated him, and was very careful in feledling 
 matter in its moft adlive hate. It was taken from the arm of a 
 boy juft before the commencement of the eruptive fever, and 
 inftantly inferted. It very fpeedily produced a fting-like feel 
 in the part. An eftlorefcence appeared, which on the fourth 
 day was rather extenfive, and fome degree of pain and ftiffnefs 
 ivere felt about the ftioulder; but on the fifth day thefe fymp- 
 toms began to difappear, and in a day or two after went en¬ 
 tirely off, without producing any effedt on the fyftem. 
 
 CASE IE 
 
 MARY BARGE, of Woodford, in this parifh, was ino¬ 
 culated with variolous matter in the year 1791. An eftlorefcence 
 
 of 
 
 1 
 
• [ *3 ] 
 
 of a palifh red colour foon appeared about the parts where the 
 matter was inferted, and fpread itfelf rather extenfively, but 
 died away in a few days without producing any variolous 
 fymptoms*. She has fince been repeatedly employed as a nurfe 
 to Small-pox patients, without experiencing any ill con- 
 fequences. This woman had the Cow Pox when (lie lived in 
 the fervice of a Farmer in this parifh thirty-one years before. 
 
 CASE V. 
 
 MRS. H--, a refpedtable Gentlewoman of this town, 
 
 had the Cow Pox when very young. She received the in- 
 
 * It is remarkable that variolous matter, when the fyftem is difpofed to reject 
 it, fhould excite inflammation on the part to which it is applied more fpeedily 
 than when it produces the Small Pox. Indeed it becomes almoft a criterion by 
 which we can determine whether the infection will be received or not. It feems 
 as if a change, which endures through life, had been produced in the adtion, or 
 difpofltion to adlion, in the veflels of the fkin ; and it is remarkable too, that 
 whether this change has been effedted by the Small Pox, or the Cow Pox, that 
 the difpofltion to Ridden cutieular inflammation is the fame on the application of 
 variolous matter. 
 
 feclion 
 
[ 14 J 
 
 fedlion in a manner that is not common: it was given by means 
 of her handling feme of the fame utenfils* which were in ufe 
 among the fervants of the family, who had the difeafe from 
 milking infe&ed cows. Her hands had many of the Cow-pox 
 fores upon them, and they were communicated to her nofe, 
 which became inflamed and very much fwoln. Soon after this 
 
 event Mrs. H~-was expofed to the contagion of the Small 
 
 Pox, where it was fcarcely poflible for her to have efcaped, had 
 fhe been fufceptible of it, as (lie regularly attended a relative 
 who had the difeafe in fo violent a degree that it proved fatal 
 to him. 
 
 In the year 1778 the Small Pox prevailed very much at 
 
 Berkeley, and Mrs. H- not feeling perfectly fatisfied re- 
 
 fpeding her fafety (no indifpofltion having followed her ex¬ 
 po fur e to the Small Pox) I inoculated her with adtive variolous 
 matter. The fame appearance followed as in the preceding 
 
 * When the Cow Pox has prevailed in the dairy, it has often been com¬ 
 municated to thofe who have not milked the cows, by the handle of the milk 
 pail. 
 
 cafes— 
 
[ 15 J 
 
 cafes—-an efflorefcence on the arm without any effed on the 
 conditution. 
 
 V 
 
 ' \ 
 
 CASE VI. 
 
 IT is a fad fo well known among our Dairy Farmers, that 
 thofe who have had the Small Fox either efcape the Cow Pox 
 or are difpofed to have it (lightly ; that as foon as the com¬ 
 plaint (hews itfelf among the cattle, adidants are procured, if 
 poflible, who are thus rendered lefs fufceptible of it, other wife 
 the bufinefs of the farm could fcarcely go forward* 
 
 In the month of May, 1796, the Cow T Pox broke out at 
 Mr. Baker’s, a Farmer who lives near this place. The difeafe 
 was communicated by means of a cow which was purchafed 
 in an infeded date at a neighbouring fair, and not one of the 
 Farmer’s cows (confiding of thirty) which were at that time 
 milked efcaped the contagion. The family confided of a man 
 fervant, two dairymaids, and a fervant boy, who, with the 
 Farmer himfelf, were twice a day employed in milking the 
 
 cattle. 
 
 / 
 
[ 16 ] 
 
 cattle. The whole of this family, except Sarah Wynne, one of 
 the dairymaids, had gone through the Small Pox. The Con- 
 fequence was, that the Farmer and the fervant boy efcaped the 
 infection of the Cow Pox entirely, and the fervant man and one 
 of the maid fervants had each of them nothing more than a fore 
 on one of their fingers, which produced no diforder in the 
 fyfiem. But the other dairymaid, Sarah Wynne, who never 
 had the Small Pox, did not efcape in fo eafy a manner. 'She 
 caught the complaint from the cows, and was aflfeded wdth 
 the fymptoms defcribed in the 5th page in fo violent a degree, 
 that flie was confined to her bed, and rendered incapable for 
 feveral days of purfuing her ordinary vocations in the farm. 
 
 March 28th, 1797, I inoculated this girl, and carefully rubbed 
 the variolous matter into two flight incifions made upon the 
 left arm. A little inflammation appeared in the ufual manner 
 around the parts where the matter was inferted, but fo early as 
 the filth day it vanifhed entirely without producing any efifed: 
 on the fyftem. 
 
 CASE 
 
[ 17 3 
 
 CASE VII. 
 
 ALTHOUGH the preceding hiilory pretty clearly evinces 
 that the conflitution is far lefs fufceptible of the conta¬ 
 gion of the Cow Pox after it has felt that of the Small Pox, 
 and although in general, as I have obferved, they who have 
 had the Small Pox, and are employed in milking cows which 
 are infedted with the Cow Pox, either efcape the diforder, or 
 have fores on the hands without feeling any general indifpofi- 
 tion, yet the animal economy is fubjedl to fome variation 
 in this refpedt, which the following relation will point out : 
 
 In the fummer of the year 1796 the Cow Pox appeared at 
 the Farm of Mr. Andrews, a confiderable dairy adjoining to 
 the town of Berkeley. It was communicated, as in the pre¬ 
 ceding inftance, by an infedted cow purchafed at a fair in the 
 neighbourhood. The family confuted of the Farmer, his wife, 
 two fons, a man and a maid fervantall of whom, except the 
 
 D 
 
 Farmer 
 
[ 18 ] 
 
 Farmer (who was fearful of the confequences) bore a part in 
 milking the cows. The whole of them, exclufive of the man 
 fervant, had regularly gone through the Small Pox; but in this 
 cafe no one who milked the cows efcaped the contagion. All 
 of them had fores upon their hands, and fome degree of general 
 indifpofition, preceded by pains and tumours in the axillae : but 
 there was no comparifon in the feverity of the difeafe as it was 
 felt by the fervant man, who had efcaped the Small Pox, and 
 by thofe of the family who had not, for, while he was confined 
 to his bed, they were able, without much inconvenience, to 
 follow their ordinary bufinefs. 
 
 February the 13th, 1797, I availed myfelf of an opportunity 
 of inoculating William Rodway, the fervant man above alluded 
 to. Variolous matter was inferted into both his arms; in the 
 right by means of fuperficial incifions, and into the left by flight 
 punctures into the cutis. Both w 7 ere perceptibly inflamed on 
 the third day. After this the inflammation about the pundtures 
 loon died away, but a fmall appearance of eryfipelas was 
 manifeft about the edges of the incifions till the eighth day, 
 
 when 
 
[ J 9 ] 
 
 when a little uneafmefs was felt for the fpace of half an hour 
 in the right axilla. The inflammation then haflily difappeared 
 without producing the moil diflant mark of affedion of the 
 fyflem. 
 
 ELIZABETH WYNNE, aged fifty-feven, lived as a fervant 
 with a neighbouring Farmer thirty-eight years ago. She was 
 then a dairymaid, and the Cow Pox broke out among the cows. 
 She caught the difeafe with the reft of the family, but, com¬ 
 pared with them, had it in a very flight degree, one very fmall 
 fore only breaking out on the little Anger of her left hand, and 
 fcarcely any perceptible indifpofltion following it. 
 
 As the malady had fhewn itfelf in fo flight a manner, and as 
 it had taken place at fo diflant a period of her life, I was happy 
 with the opportunity of trying the effeds of variolous matter 
 upon her conflitution, and on the 28th of March, 1797* ^ 
 
 D 2 ' inoculated 
 
 4 
 
\ 
 
 C 20 ] 
 
 inoculated her by making two fuperficial incifions on the left 
 arm, on which the matter was cautioufly rubbed. A little 
 efflorefcence foon appeared, and a tingling fenfation was felt 
 about the parts where the matter was inferted until the third 
 day, when both began to fubfide, and fo early as the fifth day 
 it was evident that no indifpofition would follow. 
 
 CASE IX . 
 
 ALTHOUGH the Cow Pox fhields the conftitution from 
 the Small Pox, and the Small Pox proves a protection againff: 
 its own future poifon, yet it appears that the human body 
 is again and again fufceptible of the infectious matter of the 
 Cow Pox, as the following hiflory will demonflrate : 
 
 William Smith, of Pyrton in this parifh, contracted this 
 difeafe when he lived with a neighbouring Farmer in the year 
 1780. One of the horfes belonging to the farm had fore heels, 
 and it fell to his lot to attend him. By thefe means the 
 
 infection 
 
 5* 
 
 / 
 
[ 21 ] 
 
 infe&ion was carried to the cows, and from the cows it was 
 communicated to Smith. On one of his hands were feveral 
 ulcerated fores, and he was affedled with fuch fymptoms as have 
 been before deferibed. 
 
 In the year 1791 the Cow Pox broke out at another farm 
 where he then lived as a fervant, and he became affeded with 
 it a fecond time; and in the year 1794 he was fo unfortunate 
 as to catch it again. The difeafe was equally as fevere the 
 fecond and third time as it was on the firfl*. 
 
 In the fpring of the year 1795 he was twice inoculated, but 
 no affedion of the fyftem could be produced from the variolous 
 matter,* and he has fince affociated with thofe who had the 
 Small Pox in its moll contagious Hate without feeling any effed 
 from it. 
 
 * This is not the cafe in general—a fecond attack is commonly very flight, and 
 fo, I am informed, it is among the cows. The reader will find further obferva- 
 tions on this fubjedl in the fequel. 
 
 CASE 
 
C 22 3 
 
 SIMON NICHOLS lived as a fervant with Mr. Bromedge, 
 a gentleman who reticles on his own farm in this parilh, in 
 the year 1782. He was employed in applying dreffings to 
 the fore heels of one of his mailer’s horfes, and at the fame 
 time aflilfed in milking the cows. The cows became affedled in 
 confequence, but the difeafe did not fhew itfelf on their nipples 
 till feveral weeks after he had begun to drefs the horfe. He 
 quitted Mr. Bromedge’s fervice, and went to another farm 
 without any fores upon him; but here his hands foon 
 began to be affedled in the common way, and he was much 
 indifpofed with the ufual fymptoms. Concealing the nature 
 of the malady from Mr. Cole, his new mailer, and being there 
 alfo employed in milking, the Cow Pox was communicated 
 to the cows. 
 
 Some years afterwards Nichols was employed in a farm where 
 the Small Pox broke out, when I inoculated him with feveral 
 
 2 other 
 
[ 23 ] 
 
 other patients, with whom he continued during the whole time 
 of their confinement. His arm inflamed, but neither the in¬ 
 flammation nor his aflociating with the inoculated family 
 produced the the leafl effed upon his conftitution. 
 
 CASE XE 
 
 WILLIAM STINCHCOMB was a fellow fervant with 
 Nichols at Mr. Bromedge’s Farm at the time the cattle had the 
 Cow Pox, and he was unfortunately infeded by them. His 
 left hand was very feverely affeded with feveral corroding 
 ulcers, and a tumour of conliderable fize appeared in the axilla 
 of that fide. His right hand had only one fmall fore upon it, 
 and no tumour difcovered itfelf in the correfponding axilla. 
 
 In the year 1792 Stinchcomb was inoculated with variolous 
 
 1 
 
 matter, but no confequences enfued beyond a little inflammation 
 in the arm for a few days. A large party were inoculated at 
 the fame time, fome of whom had the difeafe in a more violent 
 
 degree 
 
 l 
 
[ 24 1 
 
 ✓ 
 
 degree than is commonly feen from inoculation. He purpofely 
 affociated with them, but could not receive the Small Pox. 
 
 During the lickening of fome of his companions, their fymp- 
 toms fo ftrongly recalled to his mind his own ftate when lick- 
 ening with the Cow Pox, that he very pertinently remarked 
 their {hiking fimilarity. 
 
 CASE XII . 
 
 THE Paupers of the village of Tortworth, in this County, 
 were inoculated by Mr. Henry Jenner, Surgeon, of Berkeley, 
 in the year 1795. Among them, eight patients prefented them- 
 felves who had at different periods of their lives had the Cow 
 Pox. One of them, Hefter Walkley, I attended with that 
 difeafe when fhe lived in the fervice of a Farmer in the fame 
 village in the year 1782; but neither this woman, nor any 
 other of the patients who had gone through the Cow Pox, 
 received the variolous infection either from the arm or from 
 
 mixing 
 
C 25 J 
 
 mixing in the fociety of the other patients who were inoculated 
 at the fame time. This hate of fecurity proved a fortunate dr- 
 cumftance, as many of the poor women were at the fame time 
 in a hate of pregnancy. 
 
 CASE - XIII. 
 
 ONE inhance has occurred to me of the fyhem being afFe&ed 
 from the matter ihliing from the heels of horfes, and of its re¬ 
 maining afterwards unfufceptible of the variolous contagioa j 
 another, where the Small Pox appeared obfcurely ; and a third, 
 in which its complete exihence was pohtively afcertained. 
 
 Firh, THOMAS PEARCE, is the fon of a Smith and Farrier 
 near to this place. He never had the Cow Pox ; but, in con- 
 fequence of drelling horfes with fore heels at his lather*s, when 
 a lad, he had fores on his lingers which fuppurated, and which 
 occalioned a pretty fevere indifpolition. Six years afterwards I 
 
 i 
 
 inferted variolous matter into his arm repeatedly, without being 
 
 E able 
 
[ 26 3 
 
 ' able to produce any thing more than flight inflammation, which 
 appeared very foon after the matter was applied, and afterwards 
 I expofed him to the contagion of the Small Pox with as little 
 
 effedt*. 
 
 CASE XIV. 
 
 Secondly, Mr. JAMES COLE, a Farmer in this Parifh, had. 
 a difeafe from the fame fource as related in the preceding cafe, 
 and fome years after was inoculated with variolous matter. He 
 had a little pain in the axilla, and felt a flight indifpolition for 
 three or four hours. A few eruptions fhewed themfelves on the 
 forehead, but they very foon difappeared without advancing 
 to maturation. 
 
 * It is a remarkable fa£t, and well known to many, that we are frequently 
 
 foiled in our endeavours to communicate the Small Pox bv inoculation to black- 
 
 «/ 
 
 fmiths, who in the country are farriers. They often, as in the above inftance, 
 cither refill the contagion entirely, or have the difeafe anomaloully. Shall we not 
 he able now to account for this on a rational principle ? 
 
 CASE 
 
C 27 ] 
 
 CASE XV. 
 
 ALTHOUGH in the two former inftanees the fyflem feemed 
 to be fecured, or nearly fo, from variolous infection, by the 
 
 abforption of matter from fores produced by the difeafed heels of 
 
 *1 
 
 horfes, yet the following cafe decisively proves that this cannot 
 be entirely relied upon, until a difeafe has been generated by the 
 morbid matter from the horfe on the nipple of the cow, and 
 paffed through that medium to the human fubjedh 
 
 Mr. ABRAHAM RIDDIFORD, a Farmer at Stone in this 
 parifh, in confequence of dreffing a mare that had fore heels, 
 was affedted with very painful fores in both his hands, tumours 
 in each axilla, and fevere and general indifpofition. A Surgeon 
 in the neighbourhood attended him, who, knowing the firm- 
 larity between the appearance of the fores upon his hands and 
 thafe produced by the Cow Pox, and being acquainted alfo with 
 the effects of that difeafe on the human conftitution* allured him 
 
 E 2 that 
 
 r 
 
[ 28 ] 
 
 that he never need to fear the infection of the Small Pox; hut 
 this affertion proved fallacious, for, on being expofed to the in¬ 
 fection upwards of twenty years afterwards, he caught the 
 difeafe, which took its regular courfe in a very mild way. There 
 certainly was a difference perceptible, although it is not eafy to 
 defcribe it, in the general appearance of the puftules from that 
 which we commonly fee. Other practitioners, who vifited the 
 patient at my requeft, agreed with me in this point, though 
 there was no room left for fufpicion as to the reality of the dif¬ 
 eafe, as I inoculated fome of his family from the puftules, who 
 had the Small Pox, with its ufual appearances, in confequence. 
 
 case m 
 
 SARAH NELMES, a dairymaid at a Farmer’s near this 
 place, was infeCted with the Cow Pox from her matter’s cows 
 in May, 1796. She received the infeCtion on a part of the hand 
 which had been previoufly in a flight degree injured by a fcratch 
 from a thorn. A large puftulous fore and the ufual fymptoms 
 
 2 accompanying 
 
C 29 ] 
 
 jfl • 
 
 accompanying the difeafe were produced in confequence. The 
 pufttile was fo expreffive of the true character of the Cow Pox, 
 as it commonly appears upon the hand, that I have given a 
 reprefcntation of it in the annexed plate. The two fmall 
 puftules on the wrifts arofe alfo from the application of the virus 
 to fome minute abrahons of the cuticle, but the livid tint, if 
 they ever had any, was not confpicuous at the time I faw the 
 patient. The puftule on the fore finger fhews the difeafe in 
 an earlier ftage. It did not actually appear on the hand of this 
 young woman, but was taken from that of another, and is 
 annexed for the purpofe of reprefenting the malady after it has 
 newly appeared. 
 
 CASE XVII . 
 
 THE more accurately to obferve the progrefs of the in¬ 
 fection, I feledteii a healthy boy, about eight years old, for 
 the purpofe of inoculation for the Cow Pox. The matter was 
 
 taken 
 
[ 3 ° 3 
 
 taken from a fore on the hand of a dairymaid*, who was 
 infedled by her mailer’s cows, and it was inferted, on the 14th 
 of May, 1796, into the arm of the boy by means of two 
 fuperficial incifions, barely penetrating the cutis, each about 
 half an inch long. 
 
 On the feventh day he complained of uneafinefs in the axilla, 
 and on the ninth he became a little chilly, loll his appetite, 
 and had a flight head-ach. During the whole of this day he 
 was perceptibly indifpofed, and fpent the night with fome 
 degree of refllelTnefs, but on the day following he was perfectly 
 well. 
 
 The appearance of the incilions in their progrefs to a Hate of 
 maturation were much the fame as when produced in a limilar 
 
 * From the fore on the hand of Sarah Nelmes.—See the preceding eafe and 
 the plate. 
 
 manner 
 

C 31 ] 
 
 manner by variolous matter*. The only difference which I 
 perceived was, in the flate of the limpid fluid arifing from the 
 
 / V . 
 
 adtion of the virus, which afTumed rather a darker hue, and 
 in that of the efflorefcence fpreading round the incifions, which 
 had more of an eryfipelatous look than we commonly perceive 
 when variolous matter has been made ufe of in the fame man¬ 
 ner ; but the whole died away (leaving on the inoculated parts 
 fcabs and fubfequent efchars) without giving me or my patient 
 the leafl trouble. 
 
 In order to afcertain whether the boy, after feeling fo flight 
 an affedtion of the fyftem from the Cow Pox virus, was fecure 
 from the contagion of the Small Pox, he was inoculated the 
 ill of July following with variolous matter, immediately taken 
 from a puftule. Several flight pundtures and incifions were 
 made on both his arms, and the matter was carefully inferted. 
 
 * This appearance was in great meafure new to me, and I ever lh'all recolledt 
 the pleafing fenfations it excited ; as, from its fimilarity to the puftule produced 
 by variolous inoculation, it inconteftibly pointed out the clofe connexion between 
 the two difeafes, and almoft anticipated the refult of my future experiments. 
 
 but: 
 
[ 32 3 
 
 but no difeafe followed. The fame appearances were obferv- 
 able on the arms as we commonly fee when a patient has had 
 variolous matter applied, after having either the Cow Pox or the 
 Small Pox. Several months afterwards he was again inoculated 
 with variolous matter, but no fenfble effect was produced on 
 the conftitution. 
 
 Here my refearches were interrupted till the fpring of the 
 year 1798, when from the wetnefs of the early part of the 
 feafon, many of the farmers’ horfes in this neighbourhood 
 Were affedted with fore heels, in confequence of which the 
 Cow Pox broke out among feveral of our dairies, which afforded 
 me an opportunity of making further obfervations upon this 
 curious difeafe. 
 
 A mare, the property of a perfon who keeps a dairy in a 
 neighbouring parifli, began to have fore heels the latter end of 
 the month of February 1798, which were occafionally wafhed 
 by the fervant men of the farm. Thomas Virgoe, William 
 Wherret, and William Haynes, who in confequence became 
 
 affe&ed 
 
 < 
 
 N 
 
3 
 
 [ 33 1 
 
 affeded with fores in their hands, followed by inflamed lym¬ 
 phatic glands in the arms and axillae,. fhiverings fucceeded by 
 , heat, laflitude and general pains in the limbs. A Angle pa- 
 roxyfm terminated the difeafe; for within twenty-four hours 
 they were free from general indifpofition, nothing remaining 
 but the fores on their hands. Haynes and Virgoe, who had 
 gone through the Small Pox from inoculation, defcribed their 
 feelings as very Amilar to thofe which affebted them on ficken- 
 ing with that malady.. Wherret never had had the Small Pox. 
 Haynes was daily employed as one of the milkers at the farm, 
 and the difeafe began to fhew itfelf among the cows about ten 
 days after he Arft aflifted in wafhing the mare’s heels. Their 
 nipples became fore in the ufual way, with bluifh puftules; 
 but as remedies were early applied they did not ulcerate to any 
 extent. 1 
 
 CASE XVIII . 
 
 JOHN BAKER, a child of five years old, was inoculated 
 March 16, 1798, with matter taken from a pufcule on the hand 
 
 F of 
 
of Thomas Virgoe, one of the fervants who had been infeCted 
 from the mare’s heels. He became ill on the fixth day with 
 fymptoms limilar to thofe excited by Cow-pox matter. On the 
 eighth day he was free from indifpolition. 
 
 There was fome variation in the appearance of the puftule on 
 the arm. Although it fomewhat refembled a Small-pox puftule, 
 yet its limilitude was not fo confpicuous as when excited by 
 matter from the nipple of the cow, or when the matter has 
 palTed from thence through the medium of the human fubjedh 
 
 j 
 
 (See Plate, No. 2.) 
 
 This experiment was made to afcertain the progrefs and fub- 
 fequent effects of the difeafe when thus propagated. We have 
 feen that the virus from the horfe, when it proves infectious 
 to the human fubjeCt, is not to be relied upon as rendering the 
 fyltem fecure from variolous infection, but that the matter 
 produced by it on the nipple of the cow is perfectly fo. 
 Whether its palling from the horfe through the human conllitu- 
 tion, as in the prefent inllance, will produce a limilar effeCN 
 
 remains 
 

 
 
 
 
 
 
 
 (', /, ?> . /, 'ss j 'rs 
 
 
 // 
 
 / / Jrf 
 
[ 35 J 
 
 remains to be decided. This would now have been effected, 
 
 but the boy was rendered unfit for inoculation from having felt 
 
 \ 
 
 the effects of a contagious fever in a work-houfe, foon after this 
 experiment was made. 
 
 CASE XIX. 
 
 WILLIAM SUMMERS, a child of five years and a half 
 old, was inoculated the fame day with Baker, with matter 
 taken from the nipples of one of the infedted cows, at the farm 
 alluded to in page 32. He became indifpofed on the fixth day, 
 vomited once, and felt the ufual flight fymptoms till the eighth 
 day, when he appeared perfedtly well. The progrefs of the 
 puftule, formed by the infection of the virus was fimilar to 
 that noticed in Cafe XVII., with this exception, its being free 
 from the livid tint obferved in that inffance. 
 
 F 2 
 
 CASE 
 
E 36 1 
 
 I 
 
 CASE XX. 
 
 FROM William Summers the difeafe was transferred to 
 William Pead, a boy of eight years old, who was inoculated 
 March 28th. On the lixth day he complained of pain in the 
 axilla, and on the feventh w T as affedted with the common fymp- 
 toms of a patient fickening with the Small Pox from inocula¬ 
 tion, which did not terminate ’till the third day after the 
 feizure. So perfedt was the limilarity to the variolous fever 
 that I was induced to examine the Ikin, conceiving there 
 might have been fome eruptions, but none appeared- The 
 efflorefcent blufh around the part pundtured in the boy’s arm 
 was fo truly charadteriftic of that which appears on variolous 
 
 inoculation, that I have given a reprefentation of it. The 
 drawing was made when the puftule was beginning to die 
 away, and the areola retiring from the centre. (See Plate, 
 No. 3.) 
 
 CASE 
 
 \ 
 
In. 3 
 

CASE XXI . 
 
 APRIL 5th. Several children and adults were inoculated 
 from the arm of William Fead. The greater part of them 
 iickened on the flxth day, and were well on the feventh, but in 
 
 9} 
 
 three of the number a fecondary indifpofition arofe in confe- 
 quence of an exteniive eryfipelatous inflammation which ap¬ 
 peared on the inoculated arms. It feemed to arife from the 
 flate of the puftule, which fpread out, accompanied with fome 
 degree of pain, to about half the diameter of a fix-pence. One 
 of thefe patients was an infant of half a year old. By the 
 application of mercurial ointment to the inflamed parts (a treat¬ 
 ment recommended under flmilar circumftances in the inoculated 
 Small Pox) the complaint fubflded without giving much 
 trouble. 
 
 / ; 1 • * x 
 
 HANNAH EXCELL, an healthy girl of feven years old, 
 and one of the patients above mentioned, received the infection 
 
 from 
 
r 
 
 [ 38 ] 
 
 from the infertion of the virus under the cuticle of the arm in 
 three diftind points. The puftules which arofe in confequence, 
 fo much refembled, on the ninth day, thofe appearing from 
 the infertion of variolous matter, that an experienced Inoculator 
 would fcarcely have difcovered a fhade ot difference at that 
 period. Experience now tells me that almoft the only varia¬ 
 tion which follows confifts in the puftulous fluids remaining 
 limpid nearly to the time of its total difappearance; and not, 
 as in the dired Small Pox, becoming purulent.—(See Plate, 
 No. 4.) 
 
 CASE XXII. 
 
 FROM the arm of this girl matter was taken and inferted 
 April 12th into the arms of John Marklove, one year and a 
 half old, 
 
 Robert F. Jenner, eleven months old, 
 
 Mary Pead, five years old, and 
 Mary James, fix years old. 
 
 Among 
 
 1 
 

[ 39 ] 
 
 Among thefe Robert F. Jenner did not receive the infection. 
 The arms of the other three inflamed properly, and began to 
 affeCt the fyflem in the ufual manner; but being under fome 
 apprehenfions from the preceding Cafes that a troublefome 
 
 i 
 
 eryfipelas might arife, I determined on making an experiment 
 
 with the view of cutting off its fource. Accordingly after the 
 « 
 
 patients had felt an indifpofltion of about twelve hours, I ap¬ 
 plied in two of thefe Cafes out of the three, on the veficle 
 formed by the virus, a little mild cauftic, compofed of equal 
 parts of quick-lime and foap, and fuffered it to remain on the 
 
 i 
 
 part fix hours*. It feemed to give the children but little un- 
 eafinefs, and effectually anfwered my intention in preventing 
 the appearance of eryfipelas. Indeed it feemed to do more, 
 for in half an hour after its application, the indifpofltion of the 
 children ceafed-f, Thefe precautions were perhaps unneceffary. 
 
 * Perhaps a few touches with the lapis fepticus would have proved equally 
 efficacious. 
 
 t What effect would a fimilar treatment produce in inoculation for the Small 
 Pox ? 
 
 as 
 
* 
 
 [ 40 3 
 
 as the arm of the third child, Mary Pead, which was fuffered 
 to take its common courfe, fcabbed quickly, without any 
 eryfipelas*. 
 
 XXIII . 
 
 FROM this child’s arm matter was taken and transferred to 
 
 that of J. Barge, a boy of feven years old. He fickened oil 
 
 « f 
 
 the eighth day, went through the difeafe with the ufual flight 
 fymptoms, and without any inflammation on the arm beyond 
 the common effiorefcence furrounding the puftule, and ap¬ 
 pearance fo often feen in inoculated Small Pox. 
 
 After the many fruitiefs attempts to give the Small Pox to 
 thofe who had had the Cow Pox, it did not appear neceffary, 
 nor was it convenient to me, to inoculate the whole of thofe 
 who had been the fubjects of thefe late trials j yet I thought 
 
 * The fubfequent part of this Treatife will fufficiently fhew the proper practice 
 in cafes of inflammation of the inoculated arm. 
 
 ft 
 
C 41 ] 
 
 it right to fee the effects of variolous matter on fome of them, 
 particularly William Summers, the firfl of thefe patients who had 
 been infedted with matter taken from the cow. He was there¬ 
 fore inoculated with variolous matter from a frefh puftule; but, 
 as in the preceding Cafes, the fyflem did not feel the effedts 
 of it in the fmallef: degree. I had an opportunity alfo of having 
 this boy (Barge) and William Pead inoculated by my Nephew, 
 Mr. Henry Jenner, whofe report to me is as follows : “ I have 
 inoculated Pead and Barge, two of the boys whom you lately 
 infedted with the Cow Pox. On the fecond day the incifions 
 were inflamed, and there was a pale inflammatory flain around 
 them. On the third day thefe appearances were flill increafing 
 and their arms itched confiderably. On the fourth day the 
 inflammation was evidently fubfiding, and on the fixth it was 
 fcarcely perceptible. No fymptom of indifpofition followed. 1 ’ 
 
 To convince myfelf that the variolous matter made ufe of 
 was in a perfedt date, I at the fame time inoculated a patient 
 
 with fome of it who never had gone through the Cow Pox, 
 
 *« . 
 
 and it produced the Small Pox in the ufual regular manner. 
 
 Thefe 
 
 G 
 
[ 42 ] 
 
 Thefe experiments afforded me much fatisfa&ion, they 
 proved that the matter in paffing from one human fnbje£t to 
 another, through five gradations, loft none of its original pro¬ 
 perties, J. Barge being the fifth who received the infection 
 fucceffively from William Summers, the boy to whom it was 
 communicated from the cow. 
 
 i 
 
 Ifhall 
 
I 43 ] 
 
 I fhall now conclude this Inquiry with fome general obferva- 
 tions on the fubjeCt, and on fome others which are inter¬ 
 woven with it. 
 
 Although I prefume it may be unneceffary to produce further 
 teftimony in fupport of my affertion “ that the Cow Pox pro¬ 
 tects the human conflitution from the infection of the Small 
 Pox,” yet it affords me confiderable fatisfaCtion to fay, that 
 Lord Somerville, the Prefident of the Board of Agriculture, 
 to whom this paper was fhewn by Sir Jofeph Banks, has found 
 
 upon inquiry that the ftatements were confirmed by the con- 
 
 # _ 
 
 curring teftimony of Mr. Dollan, a furgeon, who refides in a 
 dairy country remote from this, in which thefe obfervations 
 were made. With refpeCt to the opinion adduced “ that the 
 fource of the infection is a peculiar morbid matter arifing in the 
 horfe,” although I have not been able to prove it from aCtual 
 experiments conducted immediately under my own eye, yet the 
 evidence I have adduced appears fufficient to eftablifh it. 
 
 G 2 
 
 They 
 
C 44 ] 
 
 They who are not in the habit of concluding experiments 
 may not be aware of the coincidence of circumftances neceffary 
 for their being managed fo as to prove perfectly decifive ; nor 
 how often men engaged in profeffional purfuits are liable to 
 interruptions which difappoint them almoft at the inftant of 
 their being accomplifhed : however, I feel no room for heftta- 
 tion refpeding the common origin of the difeafe, being well 
 convinced that it never appears among the cows (except it can 
 be traced to a cow introduced among the general herd which has 
 been previoufly infeded, or to an infeded fervant), unlefs they 
 have been milked by fome one who, at the fame time, has the 
 care of a horfe affeded with difeafed heels. 
 
 The fpring of the year 1797, which I intended particularly 
 
 to have devoted to the completion of this inveftigation, proved, 
 
 \ 
 
 from its drynefs, remarkably adverfe to my wifhes; for it 
 frequently happens, while the farmers* horfes are expofed to 
 the cold rains which fall at that feafon that their heels become 
 difeafed, and no Cow Pox then appeared in the neighbour¬ 
 hood. 
 
 The 
 
: , ' . ' c 45 3 
 
 The adtive quality of the virus from the horfes’ heels is 
 greatly increafed after it has adted on the nipples of the cow, 
 as it rarely happens that the horfe affedts his drefler with fores, 
 and as rarely that a milk-maid efcapes the infedtion when flie 
 milks infedted cows. It is moft adtive at the commencement of 
 the difeafe, even before it has acquired a pus-like appearance; 
 indeed I am not confident whether this property in the mat¬ 
 ter does not entirely ceafe as foon as it is fecreted in the form 
 of pus. I am induced to think it does ceafe*, and that it is the 
 thin darkifh-looking fluid only, oozing from the newly-formed 
 cracks in the heels, fimilar to what fometimes appears from 
 eryfipelatous bliflers, which gives the difeafe. Nor am I cer¬ 
 tain that the nipples of the cows are at all times in a flate to 
 receive the infedtion. The appearance of the difeafe in the 
 fpring and the early part of the fummer, when they are difpofed 
 to be affedted with fpontaneous eruptions fo much more fre¬ 
 quently than at other feafons, induces me to think, that the 
 
 * It is very eafy to procure pus from old fores on the heels of horfes. This I 
 have often inferted into fcratches made with a lancet, on the found nipples of 
 cows, and have feen no other effedts from it than fnnple inflammation. 
 
 virus 
 
[ 46 ] 
 
 virus from the horfe muH be received upon them when they are 
 in this Hate, in order to produce effects : experiments, however, 
 muff determine thefe points. But it is clear that when the Cow 
 Pox virus is once generated, that the cows cannot refift the 
 contagion, in whatever Hate their nipples may chance to be, 
 if they are milked with an infedted hand. 
 
 Whether the matter, either from the cow or the horfe will 
 affedt the found fkin of the human body, I cannot pofitively 
 determine; probably it will not, unlefs on thofe parts where 
 the cuticle is extremely thin, as on the lips for example. I 
 have known an inHance of a poor girl who produced an ulcera¬ 
 tion on her lip by frequently holding her finger to her mouth 
 to cool the raging of a Cow-pox fore by blowing upon it. The 
 hands of the farmers 1 fervants here, from the nature of their 
 
 employments, are conHantly expofed to thofe injuries which 
 
 •* > 
 
 occalion abrafions of the cuticle, to punctures from thorns and 
 fuch like accidents; fo that they are always in a Hate to feel the 
 confequences of expofure to infedtious matter. 
 
 2 
 
 It 
 
[ 47 ] 
 
 : It is lingular to obferve that the Cow Pox virus, although it 
 renders the conftitution unfufceptible of the variolous, fhould, 
 neverthelefs, leave it unchanged with refpedt to its own addon. 
 I have already produced an inftance* to point out this, and fhall 
 now corroborate it with another, 
 
 Elizabeth Wynne, who had the Cow Pox in the year 1759, 
 was inoculated with variolous matter, without effedt, in the 
 year 1797, and again caught the Cow Pox in the year 1798. 
 When I faw her, which was on the eighth day after fhe re¬ 
 ceived the infedtion, I found her affedted with general latitude, 
 fhiverings, alternating with heat, coldnefs of the extremities, 
 and a quick and irregular pulfe. Thefe fymptoms were pre¬ 
 ceded by a pain in the axilla. On her hand was one large 
 puftulous fore, which refembled that delineated in Plate No. i,*f* 
 
 * See Cafe IX. 
 
 t As I have before obferved, thefe fymptoms probably arofe from the irritation 
 of the fore, which was very painful. 
 
 It 
 
 4 
 
[ 48 3 
 
 It is curious alfo to obferve, that the virus, which with 
 refpedt to its effe&s is undetermined and uncertain previoufly 
 to its paffing from the horfe through the medium of the cow, 
 fhould then not only become more adlive, but fhould invariably 
 and completely poffefs thofe fpecific properties which induce 
 in the human conftitution fymptoms fimilar to thofe of the 
 variolous fever, and effeCt in it that peculiar change which for 
 ever renders it unfufceptible of the variolous contagion. 
 
 May it not then be reafonably conjectured, that the fource 
 of the Small Pox is morbid matter of a peculiar kind, generated 
 by a difeafe in the horfe, and that accidental circumflances may 
 have again and again arifen, ftill working new changes upon 
 it, until it has acquired the contagious and malignant form 
 under which we now commonly fee it making its devaflations 
 amongft us ? And, from a confideration of the change which , 
 the infectious matter undergoes from producing a difeafe on the 
 cow, may we not conceive that many contagious difeafes, now 
 prevalent amongft us, may owe their prefent appearance not 
 to a Ample, but to a compound origin ? For example, is it 
 
 difficult 
 
[ 49 1 
 
 difficult to imagine that the meafles, the fcarlet fever, and the 
 ulcerous fore throat with a fpotted fkin, have all fprung from the 
 fame fource, affuming fome variety in their forms according to 
 the nature of their new combinations ? The fame queftion will 
 apply refpeding the origin of many other contagious difeafes, 
 
 s 
 
 which bear a firong analogy to each other. 
 
 There are certainly more forms than one, without confider- 
 ing the common variation between the confluent and diftind, 
 in which the Small Pox appears in what is called the natural 
 way.—About feven years ago a fpecies of Small Pox^ fpread 
 through many of the towns and villages of this part of 
 Glouceflerfhire: it was of fo mild a nature, that a fatal inflance 
 was fcarcely ever heard of, and confequently fo little dreaded by 
 the lower orders of the community, that they fcrupled not to 
 hold the fame intercourfe with each other as if no infedious 
 difeafe had been prefent among them. I never faw nor heard 
 of an inflance of its being confluent. The moll accurate man¬ 
 ner, perhaps, in which I can convey an idea of it is, by faying, 
 that had fifty individuals been taken promifcuoufly and infeded 
 
 H • by 
 
1 
 
 [ 5 ° ] 
 
 by expofure to this contagion, they would have had as mild and 
 light a difeafe as if they had been inoculated with variolous 
 matter in the ufual way. The harmlefs manner in which it 
 diewed itfelf could not arife from any peculiarity either in the 
 feafon or the weather, for I watched its progrefs upwards of a 
 year without perceiving any variation in its general appearance* 
 I conlider it then as a variety of the Small Pox *. 
 
 In fome of the preceding cafes I have noticed the attention; 
 that was paid to the Hate of the variolous matter previous to the 
 experiment of inferting it into the arms of thofe who had gone 
 through the Cow Pox. This I conceived to be of great im¬ 
 portance in conducting thefe experiments, and were it always 
 properly attended to by thofe who inoculate for the Small Pox, it 
 might prevent much fubfequent mifchief and confufion. With 
 
 * My friend Dr. Hicks, of Briftol, who during the prevalence of this dif- 
 temper was refident at Gloucefter, and Phyfician to the Hofpital there, (where it 
 was feen foon after its firft appearance in this country) had opportunities of 
 making numerous obfervations upon it, which it is his intention to communicate 
 to the Public. 
 
 the 
 
\ 
 
 [ 5 l ] 
 
 the view of enforcing fo neceflary a precaution, I {hall take the 
 liberty of digrefling fo far as to point out fome unpleafant fads, 
 relative to mifmanagement in this particular, which have fallen 
 under my own obfervation. 
 
 A Medical Gentleman (now no more), who for many years 
 inoculated in this neighbourhood, frequently preferved the 
 variolous matter intended for his ufe, on a piece of lint or cotton, 
 which, in its fluid flate was put into a vial, corked, and con¬ 
 veyed into a warm pocket; a fituation certainly favourable for 
 fpeedily producing putrefadion in it. In this flate (not un- 
 frequently after it had been taken feveral days from the puftules) 
 it was inferted into the arms of his patients, and brought on 
 inflammation of the incifed parts, fwellings of the axillary 
 glands, fever, and fometimes eruptions. But what was this 
 difeafe ? Certainly not the Small Pox; for the matter having 
 from putrefadion loft, or fuffered a derangement in its fpecific 
 properties, was no longer capable of producing that malady, 
 thofe who had been inoculated in this manner being as much 
 
 H 2 fubjed 
 
[ 52 ] 
 
 fubjedt to the contagion of the Small Pox, as if they had never 
 been under the influence of this artificial difeafe; and many, 
 unfortunately, fell vidtims to it, who thought themfelves 
 in perfedt fecurity. The fame unfortunate circumffance of 
 giving a difeafe, fuppofed to be the Small Pox, with inefEca- 
 
 i 
 
 ceous variolous matter, having occurred under the diredtion of 
 fome other pradtitioners within my knowledge, and probably 
 from the fame incautious method of fecuring the variolous mat¬ 
 ter, I avail myfelf of this opportunity of mentioning what I 
 conceive to be of great importance ; and, as a further cautionary 
 hint, I (hall again digrefs fo far as to add another obfervation on 
 the fubjedt of Inoculation, 
 
 Whether it be yet afcertained by experiment, that the quantity 
 of variolous matter inferted into the fkin makes any difference 
 with refpedt to the fubfequent mildnefs or violence of the 
 difeafe, I know not; but I have the ffrongefl reafon for fup- 
 pofing that if either the pundtures or incifions be made fo deep 
 as to go through it, and wound the adipofe membrane, that 
 the rifk of bringing on a violent difeafe is greatly increafed. I 
 
 have 
 
I 
 
 [ 53 ] 
 
 have known an inoculator, whofe pra&ice was “ to cut deep 
 enough (to ufe his own expreffion) to fee a bit of fat,” and 
 there to lodge the matter. The great number of bad Cafes, in¬ 
 dependent of inflammations and abfcelTes on the arms, and the 
 fatality which attended this practice was almofl: inconceivable; 
 and I cannot account for it on any other principle than that of 
 
 the matter being placed in this lituation inffead of the fkin. 
 
 \ 
 
 It was the practice of another, whom I well remember, to 
 pinch up a fmall portion of the fkin on the arms of his patients 
 and to pafs through it a needle, with a thread attached to it 
 previoufly dipped in variolous matter. The thread was lodged 
 in the perforated parts, and confequently left in contact with the 
 cellular membrane. This practice was attended with the fame 
 ill fuccefs as the former. Although it is very improbable that 
 any one would now inoculate in this rude way by defign, yet 
 thefe obfervations may tend to place a double guard over the 
 lancet, when infants, whofe fkins are comparatively fo very 
 thin, fall under the care of the inoculator. 
 
 A very 
 
[ 54 ] 
 
 A very refpedtable friend of mine, Dr. Hardwicke, of Sod- 
 bury in this county, inoculated great numbers of patients 
 previous to the introdu&ion of the more modern method by 
 Sutton, and with fuch fuccefs, that a fatal inflance occurred as 
 rarely as fince that method has been adopted. It was the 
 doctor’s practice to make as flight an incifion as poffible upon 
 the (kin, and there to lodge a thread faturated with the variolous 
 matter. When his patients became indifpofed, agreeably to the 
 cuftom then prevailing, they were directed to go to bed, and 
 were kept moderately warm. Is it not probable then, that the 
 fuccefs of the modern practice may depend more upon the method 
 of invariably depofiting the virus in or upon the fkin, than on 
 the fubfequent treatment of the difeafe ? 
 
 I do not mean to infinuate that expofure to cool air, and 
 fuffering the patient to drink cold water when hot and thirfly, 
 may not moderate the eruptive fvmptoms and leffen the number 
 of puftules ; yet, to repeat my former obfervation, I cannot 
 account for the uninterrupted fuccefs, or nearly fo, of one 
 pra&itioner, and the wretched Hate of the patients under the 
 
 2 
 
 care 
 
t 55 3 
 
 care of another, where, in both inftances, the general treatment 
 did not differ effentially, without conceiving it to arife from 
 the different modes of inferting the matter for the purpofe of 
 producing the difeafe. As it is not the identical matter inferted 
 which is abforbed into the conftitution, but that which is, by 
 fome peculiar procefs in the animal economy, generated by it, 
 is it not probable that different parts of the human body may 
 prepare or modify the virus differently ? Although the fkin, 
 for example, adipofe membrane, or mucous membranes are all 
 capable of producing the variolous virus by the ftimulus given 
 by the particles originally depofited upon them, yet I am in¬ 
 duced to conceive that each of thefe parts is capable of producing 
 fome variation in the qualities of the matter previous to its 
 affedling the conftitution. What elfe can conftitute the dif¬ 
 ference between the Small Pox when communicated cafually 
 or in what has been termed the natural way, or when brought 
 on artificially through the medium of the fkin ? After all, are 
 the variolous particles, poffeffing their true fpecific and con¬ 
 tagious principles, ever taken up and conveyed by the lym¬ 
 phatics unchanged into the blood veffels ? I imagine not. Were 
 
 this 
 
[ 56 ] 
 
 this the cafe, fhould we not find the blood fufficiently loaded 
 
 # 
 
 with them in fome ftages of the Small Pox to communicate the 
 difeafe by inferting it under the cuticle, or by fpreading it on 
 the furface of an ulcer? Yet experiments have determined the 
 impracticability of its being given in this way ; although it has 
 been proved that variolous matter when much diluted with 
 water, and applied to the fkin in the ufual manner, will pro¬ 
 duce the difeafe. But it would be digreffing beyond a proper 
 boundary, to go minutely into this fubjeCt here. 
 
 I 
 
 At what period the Cow Pox was firft noticed here is not 
 upon record. Our oldeft farmers were not unacquainted with 
 it in their earlieft days, when it appeared among their farms 
 without any deviation from the phsenomena which it now 
 exhibits. Its connection with the Small Pox feems to have 
 
 been unknown to them. Probably the general introduction of 
 inoculation firfl occaiioned the difcovery. 
 
 Its rife in this country may not have been of very remote 
 date, as the practice of milking cows might formerly have been 
 
 in 
 
[ 57 ] 
 
 In the hands of women only ; which I believe is the cafe now 
 in fome other dairy countries, and, confequently that the cows 
 might not in former times have been expofed to the contagious 
 matter brought by the men fervants from the heels of horfes *. 
 Indeed a knowledge of the fource of the infe&ion is new in the 
 minds of moft of the farmers in this neighbourhood, but has at 
 length produced good confequences $ and it feems probable from 
 the precautions they are now difpofed to adopt, that the ap¬ 
 pearance of the Cow Pox here may either be entirely extinguifhed 
 or become extremely rare, 
 
 - * ■ » 
 
 Should it be afked whether this inveftigation is a matter of 
 mere curiofity, or whether it tends to any beneficial purpofe, 
 I fhould anfvver, that notwithflanding the happy effects of 
 Inoculation, with all the improvements which the practice has 
 
 * I have been informed from refpedtable authority that in Ireland, although 
 dairies abound in many parts of the Ifland, the difeafe is entirely unknown. The 
 reafon feems obvious. The bufinefs of the dairy is conduced by women only. 
 Where the meaneft vaffal among the men, employed there as a milker at a dairy, 
 he would feel his fituation unpleafant beyond all endurance. 
 
 I received 
 
 s 
 
C 58 ] 
 
 received Ance its Arfl introduction into this country, it not very 
 frequently produces deformity of the Ikin, and fometimes, 
 under the bcft management, proves fatal. 
 
 Thefe circumdances mud naturally create in every indance 
 fome degree of painful folicitude for its confequences. But as I 
 have never known fatal effeCts arife from the Cow Pox, even 
 when imprefl'ed in the mod unfavourable manner, producing 
 extenAve inflammations and fuppurations on the hands; and as 
 it clearly appears that this difeafe leaves the conflitution in a 
 flate of perfect fecurity from the infection of the Small Pox, 
 may we not infer that a mode of Inoculation may be introduced 
 preferable to that at prefent adopted, efpecially among thofe 
 families, which, from previous circumdances we may judge 
 to be predifpofed to have the difeafe unfavourably? It is an 
 excefs in the number of pudules which we chiefly dread in the 
 Small Pox ; but, in the Cow Pox, no pudules appear, nor does 
 it feem poflible for the contagious matter to produce the difeafe 
 from effluvia, or by any other means than contaCl, and that 
 probably not Amply between the virus and the cuticle; fo that 
 
 a Angle 
 
/ 
 
 C 59 ] 
 
 a tingle individual in a family might at any time receive it 
 without the rifk of infecting the reft, or of fpreadinga diftemper 
 that fills a country with terror. Several inftances have come 
 under my obfervation which juftify the affertion that the difeafe 
 cannot be propagated by effluvia. The firft boy whom I inocu¬ 
 lated with the matter of Cow Pox, flept in a bed, while the 
 experiment was going forward, with tw r o children who never 
 had gone through either that difeafe or the Small Pox, without 
 infedting either of them. 
 
 A young woman who had the Cow Pox to a great extent, 
 feveral fores which maturated having appeared on the hands and 
 wrifts, flept in the fame bed with a fellow dairymaid who never 
 had been infedied with either the Cow Pox or the Small Pox, 
 but no indifpofition followed. 
 
 Another infiance has occurred of a young woman on whofe 
 hands were feveral large fuppurations from the Cow Pox, who 
 was at the fame time a daily nurfe to an infant, but the com¬ 
 plaint was not communicated to the child. 
 
 I 2 
 
 In 
 
C So ] 
 
 In fome other points of view, the inoculation of this difeafe 
 appears preferable to the variolous inoculation. 
 
 y \ 
 
 V 
 
 In conflitutions predifpofed to fcrophula, how frequently we 
 fee the inoculated Small Pox, roufe into adtivity that diftrefsful 
 malady. This circumftance does not feem to depend on the 
 manner in which the diftemper has fliewn itfelf, for it has as 
 frequently happened among thofe who have had it mildly, as 
 when it has appeared in the contrary way. 
 
 There are many, who from fome peculiarity in the habit 
 refill; the common effedts of variolous matter inferted into the 
 fkin, and who are in confequence haunted through life with 
 the diftreffing idea of being infecure from fubfequent infedtion. 
 A ready mode of diflipating anxiety originating from fuch a 
 caufe muff now appear obvious. And, as we have feen that the 
 conftitution may at any time be made to feel the febrile attack of 
 Cow Pox, might it not, in many chronic difeafes be introduced 
 into the fyftem, with the probability of affording relief, upon 
 well-known phyfiological principles ? 
 
 Although 
 
 r 
 
[ 61 ] 
 
 Although I fay the fyfiem may at any time be made to feel 
 the febrile attack of Cow Pox, yet 1 have a fingle infiance 
 before me where the virus abfed locally only, but it is not in 
 the leaf; probable that the fame perfon would ref ft the abtion 
 both of the Cow Pox vims and the variolous. 
 
 Elizabeth Sarfenet lived as a dairymaid at Newpark farm, in 
 this parifh. All the cows and the fervants employed in milking 
 had the Cow Pox; but this woman, though fie had feveral 
 fores upon her fingers, felt no tumours in the axillae, nor any 
 general indifpofition. On being afterwards cafually expofed 
 to variolous infection, fie had the Small Pox in a mild way.— 
 Hannah Pick, another of the dairymaids who was a fellow- 
 fervant with Elizabeth Sarfenet when the difiemper broke out 
 at the farm, was at the fame time infected ; but this young 
 woman had not only fores upon her hands, but felt herfelf alfo 
 much indifpofed for a day or two. After this, I made feveral 
 attempts to give her the Small Pox by inoculation, but they all 
 
 proved fruitlefs. From the former Cafe then we fee that 
 
 the 
 
\ 
 
 [ & ] 
 
 the animal economy is fubjedt to the fame laws in one difeafe as 
 the other. 
 
 \ 
 
 The following Cafe, which has very lately occurred, renders 
 it highly probable that not only the heels of the horfe, but other 
 parts of the body of that animal, are capable of generating the 
 virus which produces the Cow Pox. 
 
 An extendve inflammation of eryfipelatous kind, appeared 
 without any apparent caufe upon the upper part of the thigh 
 of a fucking colt, the property of Mr. Millet, a farmer at 
 Rockhampton, a village near Berkeley. The inflammation con¬ 
 tinued feveral weeks, and at length terminated in the formation 
 of three or four fmall abfceflfes. The inflamed parts were 
 fomented, and dreffings were applied by fome of the fame 
 perfons who were employed in milking the cows. The number 
 ol cows milked was twenty-four, and the whole of them had > 
 the Cow Pox. The milkers, confifling of the farmer’s wife, 
 a man and a maid fervant, were infedted by the cows. The 
 
 i 
 
 man 
 
[ 63 ] 
 
 man fervant had previonfly gone through the Small Fox, and 
 felt but little of the Cow Pox. The fervant maid had fome 
 
 years before been infedted with the Cow Pox, and fhe alfofelt it 
 
 X 
 
 now in a flight degree. But the farmer’s wife who never had 
 gone through either of thefe difeafes, felt its effedts very 
 feverely. 
 
 That the difeafe produced upon the cows by the colt, and 
 from thence conveyed to thofe who milked them was the true 
 and not the fpurious Cow Pox*, there can be fcarcely any room 
 for fufpicion; yet it would have been more completely fatif- 
 fadtory, had the effedts of variolous matter been afcertained 
 on the farmer’s wife, but there was a peculiarity in her fitua- 
 tion which prevented my making the experiment. 
 
 Thus far have I proceeded in an inquiry, founded, as it mud: 
 appear, on the bails of experiment j in which, however, con- 
 jedture has been occafionally admitted in order to prefent to 
 
 perfons 
 
 * See P.:ge 7. 
 
.[ 64 ] 
 
 perfons well Situated for fuch difcufiions, objedts for a more 
 minute investigation. In the mean time I Shall my Self continue 
 to profecute this inquiry, encouraged by the hope of its be¬ 
 coming eflentially beneficial to mankind. 
 
 FURTHER 
 
FURTHER 
 
 OBSERVATIONS 
 
 ON THE 
 
 variola: vaccina:. 
 
ADVERTISEMENT. 
 
 The foregoing pages contain the whole of my 
 firfl Treatife on the Variola' Viccinae, publifhed 
 in June 179B. The importance of the Inquiry 
 to the whole human race naturally excited uni- 
 verfal attention. Ingenuity and induftry were fet 
 in motion : but as phyfiological difcuffions are 
 ever liable to error from the complicated nature 
 of their chara&er, I foon clearly perceived that 
 this theory, fo beneficial to mankind, was liable 
 to fall into difrepute and to be wholly difcredited 
 by the force of hafty conclufions unfounded on 
 experiment. 
 
 K 2 * 
 
 To 
 
[ 2 ] 
 
 To guard the public mind from prejudice, and 
 to enforce the neceffity of a fcrupulous precaution 
 in the conduft of inoculation with vaccine matter, 
 I was induced to offer to the world ££ Further 
 Obfervations” on the difeafe, which were pub- 
 lifhed in the beginning of the year 1799. Thefe 
 Treatifes I have here combined, together with 
 fome additions which the continuance of the 
 Inquiry has enabled me to fubmit to the public. 
 
 \ 
 
 \ 
 
 FURTHER 
 
FURTHER. 
 
 OBSERVATIONS, 
 
 &c. &c. 
 
 Although it has not been in my power to extend the 
 Inquiry into the caufes and effects of the Variola Vaccinae much 
 beyond its original limits, yet, perceiving that it is beginning to 
 excite a general fpirit of inveiligation, I think it of importance, 
 without delay, to communicate fuch fadts as have lince occur¬ 
 red, and to point out the fallacious fources from whence a difeafe 
 refembling the true Variolas Vaccinae might arife, with the 
 view of preventing thofe who may inoculate, from producing a 
 
 fpurious 
 
/ 
 
 [ 7° ] 
 
 fpurious difeafe; and further, to enforce the precaution fuggefted 
 
 i 
 
 in the former Treatife on the fubjedt, of fubduing'the inoculated 
 puftule as foon as it has fufficiently produced its influence on the 
 conftitution. From a want of due difcrimination of the real 
 exiftenee of the difeafe either in the brute or in the human 
 fubjedt, and alfo of that flage of it in which it is capable of pro¬ 
 ducing the change in the animal economy which renders it un- 
 fufceptible of the contagion of the Small Pox, unpleafant con¬ 
 fluences might enfue, the fource of which, perhaps, might 
 not be fufpedted by one inexperienced in conducing fuch ex¬ 
 periments. 
 
 My late publication contains a relation of mofl of the fadts 
 which had come under my own infpedlion at the time it was 
 written, interfperfed with fome conjectural obfervations. Since 
 then Dr. G. Pearfon has eflabliflied an inquiry into the validity 
 of my principal aflertion, the refult of which cannot but be 
 highly flattering to my feelings. ' It contains not a Angle cafe 
 which I think can be called an exception to the fadt I was fo 
 firmly imprefled with—that the Cow Pox protects the human 
 
 2 body 
 
[ 7i 3 
 
 body from the Small Pox. I have myfelf received fome further 
 confirmations, which fhall be fubjoined. I have lately alfo been 
 favoured with a letter from a gentleman of great refpedability 
 (Dr. Ingenhoufz), informing me that, on making an inquiry 
 into the fubjed in the county of Wilts, he difcovered that a 
 farmer near Caine had been infeded with the Small Pox after 
 having had the Cow Pox, and that the difeafe in each indance 
 was fo drongly charaderifed as to render the fads incontrover¬ 
 tible. The Cow Pox, it feems, from the Dodor’s information, 
 
 i 
 
 was communicated to the farmer from his cows at the time that 
 
 4 * 
 
 they gave out an ojfenfwe flench from their udders . 
 
 Some other indances have likewife been reprefented to me of 
 the appearance of the difeafe, apparently marked with its cha~ 
 raderidic fymptoms, and yet that the patients have afterwards 
 had the Small Pox. On thefe Cafes I diall, for the prefent, 
 fufpend any particular remarks, but hope that the general: 
 obfervations I have to offer in the fequel will prove of fufficient 
 weight to render the idea of their ever having had exidence,. 
 but as cafes of fpurious Cow Pox, extremely doubtful. 
 
 Ere 
 
 b 
 
[ 72 ] 
 
 Ere I proceed let me be permitted to obferve, that Truth, in 
 this and every other phyfiological Inquiry that has occupied my 
 attention, has ever been the object of my purfuit; and fhould it 
 appear in the prefent inftance that I have been led into error, 
 fond as l may appear of the offspring of my labours, I had 
 rather fee it perifh at once, than exift and do a public injury. 
 
 I fhall proceed to enumerate the fources, or what appear to 
 me as fuch, of a fpurious Cow Pox. 
 
 C 
 
 iff. That ariilng from puftules on the nipples or udder of the 
 cow; which puftules contain no fpecific virus. 
 
 2<Jly. From matter (although originally poffeffing the fpecific 
 virus) which has fuffered a decompofition, either from putre¬ 
 faction or from any other caufe lefs obvious to the fenfes. 
 
 gdly. From matter taken from an ulcer in an advanced ftage, 
 which ulcer arofe from a true Cow Pock. 
 
 4 thly. From 
 
[ 73 ] 
 
 qthly. From matter produced on the human fkin from contadf 
 with fome peculiar morbid matter generated by a horfe. 
 
 On thefe fubjedts I fhall offer fome comments. Firfl—To 
 what length puftulous difeafes of the udder and nipples of the 
 cow may extend, it is not in my power to determine; but 
 certain it is, that thefe parts of the animal are fubjedt to fome 
 variety of maladies of this nature ; and as many of thefe erup¬ 
 tions (probably all of them) are capable of giving a difeafe to the 
 human body, would it not be difcreet for thofe engaged in this 
 inveftigation to fufpend controverfy and cavil until they can 
 afcertain with precifion what is and what is not the genuine Cow 
 Pox ? 
 
 For example.—-A farmer who is not converfant with any of 
 
 thefe maladies, but who may have heard of the Cow Pox in 
 
 • • % 
 
 general terms, may acquaint a neighbouring furgeon that the 
 diftemper appears at his farm. The furgeon, eager to make an 
 'experiment, takes away matter, inoculates, produces a fore, 
 
 L uneafinefs 
 
[ 74 ] 
 
 uneafinefs in the axilla, and perhaps fome affection of the fyfterm 
 This is one way in which a fallacious idea of fecurity both in 
 the mind of the inoculator and the patient may arife ; for a 
 difeafe may thus have been propagated from a fimple eruption 
 only. 
 
 One of the fir ft objedts then of this purfuit, as I have 
 obferved, fhould be, to learn how to diftinguifh with accuracy 
 between that peculiar puftule which is the true Cow Pock, and 
 that which is fpurious. Until experience has determined this, 
 we view our object through amift. Let us for inftance fuppofe, 
 that the Small Pox and the Chicken Pox were at the fame time 
 to fpread among the inhabitants of a country which had never 
 been vifited by either of thefe diftempers, and where they were 
 quite unknown before; what confufion would arife! The re- 
 femblance between the fymptoms of the eruptive fever and 
 between the puftules in either cafe would be fo ftriking, that a 
 patient, who had gone through the Chicken Pox to any extent, 
 would feel equally eafy with regard to his future fecurity from 
 
 the 
 
 ♦ 
 
[ 75 3 
 
 the Small Pox as the perfon who had actually pafteq through 
 that difeafe. Time and future obfervation would draw the line 
 of diftindlion. 
 
 So I prefume it will be with the Cow Pox until it is more 
 generally underflood. All cavilling therefore on the mere report 
 of thofe who tell us they have had this diftemper, and are after¬ 
 wards found to be fufceptible of the Small Pox, fliould be fuf- 
 pended. To illuftrate this, I beg leave to give the following 
 hiftory: ^ 
 
 SARAH MERLIN, of the parifh of Eaftington in this 
 county, when about thirteen or fourteen years of age, lived as a 
 fervant with farmer Clarke, who kept a dairy, confining of 
 about eighteen cows, at Stonehoufe, a neighbouring village. The 
 nipples and udders of three of the cows were extenfively affeefted. 
 with large white blifters. Thefe cows the girl milked daily, and 
 at the fame time fhe aftifted, with two others, in milking the 
 reft of the herd. • It fbon appeared that the difeafe was commu¬ 
 nicated to the girl. The reft of the cows efcaped the infe&ion, 
 
 L 2 although 
 
[ 76 ] 
 
 although they were milked feveral days after the three above 
 fpecified had thefe eruptions on the nipples and udders, and even 
 after the girl’s hand became fore. The two others who were 
 engaged in milking, although they milked the cows indifcrimi- 
 nately, received no injury. On the fingers of each of the girl’s 
 hands there appeared feveral large white blifters, fhe fuppofes 
 about three or four on each finger. The hands and arms inflamed 
 and fwelled, but no conflitutional indifpofition followed. The 
 fores were anointed with fome domeflic ointment, and got well 
 without ulcerating. 
 
 As this malady was called the Cow Pox, and recorded as fuch 
 in the mind of the patient, fhe became regardlefs of the Small 
 Pox; but, on being expofed to it fome years afterwards, fhe was, 
 infedted, and had a full burthen. 
 
 Now had any one converfant with the habits of the difeafe 
 heard this hiflory, they would have had no hefitation in pro¬ 
 nouncing it a cafe of fpurious Cow Pox; confidering its de¬ 
 viation in the numerous bliflers which appeared on the girl’s 
 
 hands ; 
 
[ 77 ] 
 
 hands; their termination without ulceration ; its not proving* 
 more generally contagious at the farm either among the cattle or 
 
 thofe employed in milking ; and confidering alfo that the patient 
 felt no general indifpofition , although there veas Jo great a 
 number of veficles » 
 
 This is perhaps the mofl deceptions form in which an erup¬ 
 tive difeafe can be communicated from the cow, and it certainly 
 requires fome attention in difcriminating it. The mofl: perfedf 
 criterion by which the judgment may be guided, is perhaps 
 that adopted by thofe who attend infedted cattle. Thefe white 
 binders on the nipples, they fay, never eat into the flefhy parts 
 like thofe which are commonly of a bluifh cad:, and which 
 
 l 
 
 conhitute the true Cow Pox , but that they affedt the fkin only, 
 quickly end in fcabs, and are not nearly fo infectious. 
 
 That which appeared to me as one caufe of fpurious eruptions,, 
 I have already remarked in the former Treatife, namely, the 
 tranlition that the Cow makes in the fpring from a poor to a 
 nutritious diet,, and from the udder's becoming at this time 
 
 more 
 
[ 78 3 
 
 more vafcular than ufual for the fupply of milk. But there is 
 
 another fource of inflammation andjpuftules which I believe is 
 not uncommon in all the dairy counties in the well of England. 
 
 A cow intended to be expofed for fale, having naturally a fmall 
 
 / 
 
 udder, is previoufly for a day or two neither milked artificially, 
 nor is hdr calf fuffered to have accefs to her. Thus the milk is 
 preternaturally accumulated, and the udder and nipples become 
 greatly diftended. The confequences frequently are, inflam¬ 
 mation and eruptions which maturate. 
 
 Whether a difeafe generated in this way has the power of 
 affedting the conflitution in any peculiar manner, I cannot pre¬ 
 fume pofitively to determine. It has been conjedtured to have 
 been a caufe of the true Cow Pox, though my inquiries have 
 not led me to adopt this fuppofition in any one inftance; on the 
 contrary, I have known the milkers affedted by it, but always 
 found that an affedtion thus induced left the fyftem as fufcep- 
 tible of the Small Pox as before. 
 
 « 
 
 What is advanced in my fecond pofition, I confider alfo of 
 
 very 
 
V 
 
 [ 79 1 
 
 very great importance, and I could widi it to be ftrongly im- 
 prefTed on the minds of all who may be difpofed to conclude 
 haftily on my obfervations, whether engaged in their invedi- 
 gation by experiments or not.—To place this in its cleared: 
 point of view (as the fimilarity between the adtion of the Small 
 Pox and the Cow Pox matter is fo obvious) it will be neceflary 
 to condder what we fometimes obferve to take place in inocu- 
 lation for the Small Pox when imperfedt variolous matter is made 
 ufe of. The concife hi dory on this fubjedt that was brought 
 forward refpedting what I had obferved in this neighbourhood*, 
 I perceive by a reference lince made to the Memoirs of the 
 Medical Society of London, may be conlidered as no more than 
 a corroboration of the fadls very clearly detailed by Mr. Kite-f. 
 To this copious evidence I have to add dill more in the 
 following communications from Mr. Earle, furgeon, of 
 
 * Inquiry into the Caufes and Effects of the Variolse Vaccinas, page 51 „ 
 
 t See an account of fome anomalous appearances confequent to the inocula¬ 
 tion of the Small Pox, by Charles Kite, Surgeon, of Gravefend, in the 
 Memoirs of the Medical Society of London.. Vol iv. page 114. 
 
 2 
 
 Frampton- 
 
[ 8o ] 
 
 Frampton-upon-Severn, in this county, which I deem the more 
 valuable, as he has with much candour permitted me to make 
 them public. / 
 
 \ 
 
 “ Sir, 
 
 “ I have read with fatisfadlion your late publication on the 
 Variolae Vaccinae, and being, among many other curious cir- 
 cumftances, particularly ftruck with that relating to the inefficacy 
 of Small-pox matter in a particular ilate, I think it proper to 
 lay before you the following fadts which came within my own 
 knowledge, and which certainly tend to ftrengthen the opinions 
 advanced in pages 51 and 52 of your Treatife. 
 
 “ In March 1784, a general inoculation took place at Arling- 
 ham in this county. I inoculated feveral patients with adtive 
 variolous matter, all of whom had the difeafe in a favourable 
 way; but my matter being all ufed, and not being able to 
 procure any more in the ftate I wifhed, I was under the neceffity 
 of taking it from a puftule which, experience has fince proved, 
 was advanced too far to anfwer the purpofe I intended. Of five 
 
 perfons 
 
C 81 ] 
 
 \ 
 
 perfons inoculated with this laid matter, four took the Small Pox 
 afterwards in the natural way; one of whom died, three re¬ 
 covered, and the other, being cautioned by me to avoid as much 
 as poffible the chance of catching it, efcaped from the difea ’ 
 through life. He died of another diforder about two years ago. 
 
 “ Although one of thefe cafes ended unfortunate, yet 1 cannot 
 fuppofe that any medical man will think me carelefs or inatten¬ 
 tive in their management; for I conceive the appearances were 
 fuch as might have induced any one to fuppofe that the perfons 
 were perfectly fafe from future infection. Inflammation in every 
 cafe took place in the arm, and fever came on with a confiderable 
 degree of pain in the axilla. In fome of their arms the inflam¬ 
 mation and fuppuration were more violent than is commonly 
 obferved when perfedt matter is made ufe of; in one there was 
 an ulcer which call; off feveral large houghs. About the ninth 
 day eruptions appeared, which died away earlier than common 
 without maturation.—From thefe circumftances I fliould fuppofe 
 that no medical practitioner would fcarcely have entertained a 
 doubt but that thefe patients had been infedted with a true Small 
 
 Pox 
 
 \ 
 
 M 
 
t 8a J 
 
 Pox; yet I muft confefs that fome fmall degree of doubt pre- 
 fented itfelf to me at the fpeedy difappearance of the eruptions p 
 and in order, as far as I could, to afcertain their fafety, I fent 
 one of them to a much older practitioner than myfelf. This 
 gentleman, on hearing the circumftance of the cafe, pronounced 
 the patient perfectly fecure from future infection. 
 
 i 
 
 “ The following faCls are alfo a Unking proof of the truth of 
 
 ) 
 
 your obfervations on this fubjeCt: 
 
 “ In the year 1789 I inoculated three children of Mr. Coaley, 
 of Hurff-farm in this county. The arms inflamed properly r 
 fever and pain in the axilla came on precifely the fame as in the 
 former cafes, and in ten days eruptions appeared, which difap- 
 peared in the courfe of two days. I muft obferve that the 
 matter here made ufe of was procured for me by a friend: but 
 no doubt it was in an improper flate; for, from the fimilarity of 
 thefe cafes to thofe which happened at Arlingham five years 
 
 T 
 
 before, I was fomewhat alarmed for their fafety, and defired to 
 inoculate them again; which being permitted, I was particularly 
 
 careful 
 
 1 
 
[ 83 ] 
 
 i 
 
 ( 
 
 careful to procure matter in its moH perfed Hate. Ail the 
 children took the Small Pox from this fecond inoculation, and 
 all had a very full burthen. Thefe fads I conceive Hrikingly 
 corroborate your opinion relative to the different Hates of matter; 
 for in both the inHances that I have mentioned it was capable 
 of producing fomething Hrongly refembling the true Small Pox, 
 although it afterwards proved not to be fo. 
 
 “ As I think the communication of thefe Cafes is a duty I 
 owe to the Public, you are at liberty to make what ufe you 
 pleafe of this letter. 
 
 “ I remain, &c. 
 
 Frampton-upon-Severn, Gloucefterftuve, 
 November 10, 1798. 
 
 “ John Earle. 
 
 “ P. S. I think it necelfary to oblerve, that I can pronounce 
 with the greatefl certainty, that the matter with which the Arling- 
 ham patients were inoculated was taken from a true Small Pox 
 puHule. I took it myfelf from a fubjed that had a very full 
 burthen. ** 
 
 
 Certain then it is that variolous matter may undergo fuch a 
 
 M 2 change 
 
L 84 ] 
 
 change from the putrefactive procefs, as well as from fome of 
 the more obfcure and latent procefles of nature, as will render it 
 incapable of giving the Small Pox in fuch a manner as to fecure 
 the human conlHtution from future infection, although we fee at 
 the fame time it is capable of exciting a difeafe which bears fo 
 ftrong a refemblance to it, as to produce inflammation and matter 
 in the incifed fkin (frequently indeed more violent than when it 
 produces its effedts perfectly), fwelling of the axillary glands, 
 general indifpofition, and eruptions. So ftrongly perfuaded was 
 the gentleman, whofe practice I have mentioned in page 51 of 
 the late Treatife, that he could produce a mild Small Pox by his 
 mode of managing the matter, that he fpoke of it as a ufeful 
 difcovery, until convinced of his error by the fatal confequence 
 which enfued. 
 
 After this ought we to be in the fmalleft degree furprifed to 
 hnd, among a great number of individuals who by living in 
 dairies have been cafually expofed to the Cow Pox virus w-hen 
 in a flate analogous to that of the Small Pox above defcribed, 
 fome, who may have had the difeafe fo imperfectly as not to 
 
 render 
 
[ 8 5 J 
 
 render them fecure from variolous attacks ? For the matter, when 
 bur ft from the puftules on the nipples of the Cow, by being 
 expofed, from its lodgment there, to the heat of an inflamed 
 furface, and from being at the fame time in a fituation to be 
 occaflonally moiflened with milk, is often likely to be in a ftate 
 conducive to putrefaction j and thus, under fome modification 
 of decompofition, it muft of courfe fometimes find accefs to the 
 hand of the milker in fuch a way as to infect him. What con- 
 fufion fhould w r e have, were there no other mode of inoculating 
 the Small Pox than fuch as would happen from handling the 
 difeafed fkin of a perfon labouring under that di{temper in 
 fome of its advanced and loathfome ftages ! It mult be obferved, 
 that every cafe of Cow Pox in the human fpecies, whether com¬ 
 municated by defign or otherwife, is to be confidered as a cafe 
 of inoculation. And here I may be allowed to make an obferva- 
 tion on the cafe of the farmer communicated to me by Dr. Ingen- 
 houfz. That he was expofed to the matter when it had under¬ 
 gone the putrefactive change, is highly probable from the Doctor's 
 
 obferving that the fick cows at the farm gave out an offensive 
 Jienchfrom their udders . However, I muft remark, that it is 
 
 unufual 
 
[ 86 ] 
 
 uiiufual for cattle to fuffer to fucli an extent, when difordered 
 with the Cow Pox, as to make a by-dander fendble of any ill 
 fmell. I have often dood among a herd which had the didemper 
 without being confcious of its prefence from any particular 
 effluvia. Indeed, in this neighbourhood it commonly receives 
 an early check from efcharotic applications of the cow leech. It 
 has been conceived to be contagious among cows without con¬ 
 tact ; but this idea cannot be well founded, becaufe the cattle in 
 one meadow do not infeCt thofe in another (although there may 
 be no other partition than a hedge) unlefs they be handled or 
 milked by thofe who bring the infectious matter with them; 
 and of courfe the fmalleil particle imaginable, when applied to a 
 part fufceptible of its influence, may produce the effeCt. Among 
 the human fpecies it appears to be very clear, that the difeafe is 
 produced by contaCt only. All my attempts, at lead, to com¬ 
 municate it by effluvia have hitherto proved ineffectual. 
 
 As well as the perfeCt change from that date in which 
 variolous matter is capable of producing full and decidve effects 
 on the conditution, to that wherein its fpecidc properties are 
 
 entirely 
 
[ 8 7 ] 
 
 % 
 
 entirely loft, it may reafonably be fuppofed that it is capable of 
 undergoing a variety of intermediate changes. The following 
 lingular occurrences in ten cafes of inoculation, obligingly com¬ 
 municated to me by Mr. Trye, Senior Surgeon to the Infirmary 
 at Gloucefter, feem to indicate that the variolous matter, previoufly 
 to its being taken from the patient for the intended purpofe, 
 was beginning to part with fome of its original properties, or, 
 in other words, that it had buffered a partial decompofition. 
 Mr. Trye fays, “ I inoculated ten children with matter taken 
 at one time and from the fame fubjedt. I obferved no peculiarity 
 in any of them previoufly to their inoculation, nor did any thing 
 remarkable appear in their arms till after the decline of the 
 difeafe. Two infants of three months old had eryfipelas about 
 the incifions, in one of them extending from the fhoulders to the 
 fingers ends. Another infant had abfceffes in the cellular fub- 
 ftance in the neighbourhood of the incifions, and five or fix of 
 the reft had axillary abfceffes. The matter was taken from the 
 diftindt Small Pox late in its progrefs, and when fome puftules 
 had been dried. It was received upon glafs, and flowly dried 
 by the fire. All the children had puftules which maturated, 
 
 fo 
 
 l 
 
I 
 
 [ 88 ] 
 
 fo that I fuppofe them all fecure from future infection ; at lead, 
 as fecure as any others whom I have ever inoculated. My 
 pradtice never afforded a fore arm before. 5 ’ 
 
 In regard to my former obfervation on the improper and 
 dangerous mode of preferving variolous matter, I ihall here 
 remark, that it feems not to have been clearly underflood. 
 Finding that it has been confounded with the more eligible 
 modes of prefervation, I will explain myfelf further. When the 
 matter is taken from a fit puflule and properly prepared for 
 prefervation, it may certainly be kept without lofing its fpecific 
 properties a great length of time ; for inflance, when it is pre- 
 vioufly dried in the open air on fome compact body, as a quill 
 or a piece of glafs, and afterwards fecured in a fmall vial*. But 
 when kept feveral days in a flate of moiilure, and during that 
 time expofed to a warm temperature, I do not think it can be 
 relied upon as capable of giving a perfect difeafe, although, as I 
 
 * Thus prepared, the Cow Pox virus was found perfe&ly a&ive, and pof- 
 feffing all its fpecific properties, at the end of three months. 
 
 have 
 
[ 8 9 ] 
 
 have before obferved, the progrefs of the fymptoms arifing from 7 
 the adion of the impeded matter bear fo ftrong a refemblance 
 to the Small Pox when excited completely. 
 
 3dly. That the firft formed virus, or what conftitutes the 
 true Cow Pock puftule, invariably poffeffes the power I have 
 afcribed to it, namely, that of affeding the conftitution with 
 a fpecific difeafe, is a truth that no fubfequent occurrence has 
 yet led me to doubt. But as I am now endeavouring to guard 
 the public as much as poffible again ft erroneous conclufons, I 
 fhall obferve, that when this puftule has degenerated into an 
 ulcer (to which Bate it is fometimes difpofed to pafs unlefs 
 timely checked) I fufped that matter poffeffing very different 
 properties may fooner or later be produced ; and although it may 
 have paffed that ftage wherein the fpecific properties of the matter 
 fecreted are no longer prefent in it, yet when applied to a fore 
 (as in the cafual way) it might difpofe that fore to ulcerate, 
 and from its irritation the fyftem would probably become 
 affeded ; and thus, by a fuming fome of its ftrongeft charaders, 
 it would imitate the genuine Cow Pox. 
 
 N 
 
 From 
 
[ 9 ° 3 
 
 From the preceding obfervations on the matter of Small Pox 
 when decompofed, it mufl, I conceive, be admitted, that Cow 
 Pox matter in the ftate now deferibed may produce a difeafe, the 
 effects of which may be felt both locally and generally, yet that 
 the difeafe thus induced may not be effe&ual in obviating the 
 future effects of variolous contagion. In the cafe of Mary 
 Miller, related by Mr. Kite in the volume above alluded to, it 
 appears that the inflammation and fuppuration of the inoculated 
 arm were more than ufually fevere, although the fyftem under¬ 
 went no fpecific change from the adtion of the virus; which 
 appears from the patient’s fickening feven weeks afterwards with 
 the natural Small Pox, which went through its courfe. Some 
 of the Cafes communicated by Mr. Earle tend further to confirm 
 this fadt, as the matter there manifeftly produced ulceration on 
 the inoculated part to a conflderable extent. 
 
 4thly. Whether the Cow Pox is a fpontaneous difeafe in the 
 cow, or is to be attributed to matter conveyed to the animal, as 
 i have conceived, from the horfe, is a queflion, which though 
 I fhall not attempt now fully to difeufs, yet I fhall digrefs fo far 
 
 as 
 
[ 91 1 
 
 as to adduce fome further obfervations, and to give my reafonS 
 more at large for taking up an opinion that to fome has appeared 
 fanciful. The aggregate of tnefe obfervations, though not 
 amounting to pofitive proof, forms prefumptive evidence of fo 
 forcible a kind, that I imagine it might on any other perfon 
 have made the fame imprefiion it did on me, without fixing 
 the imputation of credulity. 
 
 Firft. I conceived this was its fource, from obferving that 
 where the Cow Pox had appeared among the dairies here (unlefs 
 it could be traced to the introduction of an infedted cow or fer- 
 vant) it had been preceded at the farm by a horfe difeafed in the 
 manner already deferibed, which horfe had been attended by 
 fome of the milkers, 
 
 % 
 
 Secondly. From its being a popular opinion throughout this 
 great dairy country, and from its being infilled on by thofe who 
 here attend fick cattle. 
 
 Thirdly. From the total abfence of the difeafe in Ireland and 
 
 N 2 Scotland, 
 
[ 92 3 
 
 Scotland, where the men fervants are not employed in the 
 
 dairies*. 
 
 Fourthly. From having obferved that morbid matter generated 
 by the horfe frequently communicates, in a cafual way, a difeafe 
 to the human fubjed fo like the Cow Pox, that in many cafes 
 it would be difficult to make the diftindion between one and 
 the other -f\ 
 
 Fifthly. From being induced to fuppofe from experiments, 
 that fome of thofe who had been thus affeded from the horfe 
 refitted the Small Pox. 
 
 Sixthly. From the progrefs and general appearance of the 
 puftule on the arm of the boy whom I inoculated with matter 
 taken from the hand of a man infeded by a horfe ; and from the 
 
 * This information was communicated to me from the firft authority. 
 
 t The found fkin does not appear to be fufceptible of this virus when inferted 
 into it, but, when previoufly difeafed from little accidents, its effedts are often 
 conspicuous. 
 
 fimilarity 
 
 4 
 
[ 93 J 
 
 « 
 
 Umilarity to the Cow Pox of the general conditutional fymptoms 
 which followed*. 
 
 i 
 
 I fear it would be trefpafling too far to adduce the general 
 teftimony of our farmers in fupport of this opinion ; yet I beg 
 leave to introduce an extract of a letter on this fubjedt from the 
 
 l 
 
 Rev. Mr. Moore, of Chalford Hill, in this county. 
 
 “ In the month of November 1797, my horfe had difeafed 
 heels, which was certainly what is termed the greafe j and at a 
 fhort fubfequent period my cow was alfo affedted with what a 
 neighbouring farmer (who was converfant with the camplaints 
 
 * This Cafe (on which I laid no inconfiderable ftrefs in my late Treatife, as 
 prefumptive evidence of the fail adduced) feems to have been either miftaken 
 or overlooked by thofe who have commented upon the fubjed.—See Cafe xviii, 
 page 33. The boy unfortunately died of a fever at a parifh workhoufe before I 
 had an opportunity of obferving what effects would have been produced by 
 the matter of Small Pox.—The experiments publifhed by Mr. Simmons of 
 Manchefter, and others on the fubjed, with the view of refuting this Theory 
 appear to have but little weight, as even the Cow-pock virus itfelf when re¬ 
 peatedly introduced into the found nipples of cows by means of a lancet,, was 
 found to produce no effed. 
 
 of 
 
C 94 ] 
 
 of cattle) pronounced to be the Cow Pox, which he at the fame 
 time obferved my fervant would be infedted with : and this 
 proved to be the cafe; for he had eruptions on his hands, face, 
 and many parts of the body, the puftules appearing large, and 
 not much unlike the Small Pox, for which he had been inocu¬ 
 lated a year and a half before, and had then a very heavy bur¬ 
 then. The puftules on the face might arife from contadt with his 
 hands, as he had a habit of rubbing his forehead, where the fores 
 were the larged; and thickefl, 
 
 “ The boy aiTociated with the farmer’s fons during the con¬ 
 tinuance of the difeafe, neither of whom had had the Small Pox, 
 but they felt no ill effedts whatever. He was not much indif- 
 pofed, as the difeafe did not prevent him from following his 
 occupations as ufual. No other perfon attended the horfe or 
 milked the cow, but the lad above mentioned. I am firmly of 
 opinion that the difeafe in the heels of the horfe, which was a 
 virulent greafe, was the origin, of the fervant’s and the cow’s 
 malady.” 
 
 But 
 
[ 95 1 
 
 But to return to the more immediate objedt of this pro¬ 
 portion. 
 
 From the fimilarity of fymptom.s, both conftitutional and 
 local, between the Cow Pox and the difeafe received from 
 morbid matter generated by a horfe, the common people in this 
 neighbourhood when infedied with this difeafe, through a 
 flrange perverfion of terms, frequently call it the Cow Pox. 
 Let us fuppofe then fuch a malady to appear among fome of the 
 fervants at a farm, and at the fame time that the Cow Pox were 
 to break out among the cattle ; and let us fuppofe too that fome 
 of the fervants were infedted in this way, and that others re¬ 
 ceived the infedtion from the cows. It would be recorded at 
 the farm, and among the fervants themfelves wherever they 
 might afterwards be difperfed, that they had all had the Cow 
 Pox. But it is clear that an individual thus infedted from the 
 horfe, would neither be for a certainty fecure himfelf, nor 
 would he impart fecurity to others were they inoculated by virus 
 thus generated. He hill would be in danger of taking the Small 
 Pox. Yet were this to happen before the nature of the Cow Pox^ 
 
 be 
 
 i 
 
[ 96 3 
 
 be more maturely confidered by the public, my evidence on the 
 fubjed might be depreciated nnjuftly. For an exemplification 
 of what is here advanced relative to the nature of the infection 
 when received di redly from the horfe, fee Inquiry into the 
 Caufes and Ededs of the Variolae Vaccine, pages 25, 26, 27, 
 28, and page 33 ; and by way of further example, I beg leave 
 to fubjoin the following intelligence received from Mr. Fewder, 
 Surgeon, of Thornbury, in this county, a gentleman perfectly 
 well acquainted with the appearances of the Cow Fox on the 
 human fubjed. 
 
 “ WILLIAM MORPvIS, aged thirty-two, fervant to Mr. 
 Cox of Almonfbury, in this county, applied to me the 2d of 
 April, 1798. He told me, that four days before, he found a 
 iiiffhefs and fwelling in both his hands, which were fo painful, 
 it was with difficulty he continued his work ; that he had been 
 ieized with pain in his head, fmall of the back, and limbs, and 
 with frequent chilly fits fucceeded by fever. On examination I 
 found him dill affeded with thefe fymptoms, and that there was 
 a great prodration of drength. Many parts of his hands on 
 
 the 
 
t 97 ] 
 
 the in fide were chapped, and on the middle joint of the thumb 
 of the right hand there was a fmall phagedenic ulcer, about the 
 fize of a large pea, difcharging an ichorus fluid. On the 
 
 middle finger of the fame hand there was another ulcer of a 
 
 \ - 
 
 fimilar kind. Thefe fores were of a circular form, and he 
 defcribed their firfi appearance as being fomewhat like blifters 
 arifing from a burn. He complained of exceflive pain, which 
 extended up his arm into the axilla. Thefe fymptoms and 
 appearances of the fores were fo exactly like the Cow Pox, that 
 I pronounced he had taken the diflemper from milking cows. 
 Pie afliired me he had not milked a cow for more than half a year, 
 and that his mafler’s cows had nothing the matter with them. 
 
 I then afked him if his mafier had a greafy horfe ? which he 
 anfvvered in the affirmative; and further faid, that he had con- 
 flantly dreffed him twice a day for the lafl three weeks or more, 
 and remarked that the fmell of his hands was much like that of 
 the horfe’s heels. On the ryh of April I again faw him, and 
 found him ftill complaining of pain in both his hands, nor were 
 his febrile fymptoms at all relieved. The ulcers had now fpread 
 to the fize of a feven-fhilling gold coin, and another ulcer, which 
 
 O I had 
 
[ 98 ] 
 
 I had not noticed before, appeared on the firft joint of the fore¬ 
 finger of the left hand, equally painful with that on the right. I 
 ordered him'to bathe his hands in warm bran and water, applied 
 efcharotics to the ulcers, and wrapped his hands up in a foft 
 cataplafm. The next day he was much relieved, and in fome- 
 thing more than a fortnight got well. He loft his nails from 
 the thumb and fingers that were ulcerated. 
 
 l 
 
 The fudden difappearance of the fymptoms in this cafe after 
 the application of the efcharotics to the fores is worthy of obfer- 
 vation ; it feems to fhew that they were kept up by the irritation 
 of the ulcers. 
 
 The general fymptoms which I have already defcribed of the 
 Cow Pox, when communicated in a cafual way to any great 
 extent, will, I am convinced, from the many Cafes I have feen, 
 be found accurate ; but from the very flight indifpofition which 
 enfues in cafes of inoculation, where the puftule after affedting 
 the conflitution, quickly runs into a fcab fpontaneoufly, or is 
 artificially fuppreffed by fome proper application, I am induced 
 
 to 
 
t 99 3 
 
 to believe that the violence of the fymptoms may be afcribed to 
 the inflammation and irritation of the ulcers (when ulceration 
 takes place to any extent, as in the cafual Cow Pox), and that 
 the conftitutional fymptoms which appear during the prefence 
 of the fore while it afliimes the charadter of a puftule only, are 
 felt but in a very trifling degree. This mild affedtion of the 
 fyftem happens when the difeafe makes but a flight local im- 
 preflion on thofe who have been accidentally infedted by cows; 
 and, as far as I have feen, it has uniformly happened among 
 
 thofe who have been inoculated, when a puftule only and no 
 great degree of inflammation or any ulceration has taken place 
 from the inoculation. The following Cafes will ftrengthen this 
 opinion. » 
 
 The Cow Pox appeared at a farm in the village of Stonehoufe, 
 in this county, about Michaelmas laft, and continued gradually 
 to pafs from one cow to another till the end of November. On 
 the 26 th of that month fome ichor us matter was taken from a 
 cow and dried upon a quill. On the 2 d of December lome of 
 it was inferted into a fcratch, made fo fuperfleial that no blood 
 
 O 2 appeared, 
 
C 100 ] 
 
 appeared, on the arm of Sufan Phipps, a child feven years 
 old. The common inflammatory appearances took place in 
 confequence, and advanced till the fifth day, when they had, 
 fo much fubfided, that I did not conceive any thing further 
 would enfue. 
 
 / 
 
 6th. Appearances flationary. 
 
 yth. The inflammation began to advance. 
 
 8th. A vefication perceptible on the edges, forming, as in the 
 inoculated Small Pox, an appearance not unlike a grain of 
 wheat, with the cleft or indention in the centre. 
 
 9th. Pain in the axilla. 
 
 loth. A little head-ache; pulfeiio; tongue not difcolouredj 
 countenance in health. 
 
 * 
 
 nth.—12th. No perceptible illnefs; pulfe about 100. 
 
 13th. The puffule was now furrounded by an efflorefcence,. 
 interfperfed with very minute confluent puftules to the extent of 
 about an inch. Some of thefe puftules advanced in fize and 
 maturated. So exabt was the refemblance of the arm at this 
 ftage to the general appearance of the inoculated Small Pox, that 
 
 Mr. D. 
 
 / 
 
[ 101 ] 
 
 Mr. D. a neighbouring furgeon, who took fome matter from 
 it, and who had never feen the Cow Pox before, declared he 
 could not perceive any difference*. The child’s arm now 
 fhewed a difpofition to fcab, and remained nearly flationary for 
 two or three days, when it began to run into an ulcerous Rate ; 
 
 and then commenced a febrile indifpofltion accompanied with an 
 
 » 
 
 increafe of axillary tumour. The ulcer continued fpreading near 
 a week, during which time the child continued ill, when it 
 increafed to a fize nearly as large as a fhilling. It began now to 
 difcharge pus ; granulations fprung up, and it healed. This 
 child had before been of a remarkably fickly conflitution, but is 
 now in very high health, 
 
 * That the Cow Pox was a fuppofed guardian of the conditution from the 
 
 adtion of the Small Pox, has been a prevalent idea for a long time pad ; but 
 
 the fimilarity in the conditutional ede£ts between one difeafe and the other 
 
 could never have been fo accurately obferved, had not the inoculation of the 
 
 Cow Pox placed it in a new and dronger point of view. This pra&ice too has 
 
 # 
 
 fhewn us what before lay concealed, the rife and progrefs of the pudule formed 
 by the infertion of the virus, which places in a mod confpicuous light its driking 
 refemblance to the pudule formed from the inoculated Small Pox. 
 
 MARY 
 
[ 102 ] 
 
 MARY HEARN, twelve years of age, was inoculated with 
 matter taken from the arm of Sufan Phipps. - 
 
 6th day. A puflule beginning to appear, flight pain in the axilla. 
 jth. A diflindt veiicle formed. 
 
 8th. The veficle increafing; edges very red ; no deviation in 
 its appearance at this time from the inoculated Small Pox. 
 
 C)th. No indifpofition; puftule advancing. 
 
 loth. The patient felt this evening a flight febrile attack. 
 
 lith. Free from indifpofition. 
 
 12th.—13th. The fame. 
 
 14th. An efflorefcence of a faint red colour extending feveral 
 inches round the arm. The puflule beginning to fliew a dif- 
 pofition to fpread, was dreffed with an ointment compofed of 
 hydrarg, nit. rub. & ung . cerce. The efflorefcence itfelf was 
 covered with a plafter of ung. hydr. fort .—In fix hours it was 
 examined, when it was found that the efflorefcence had totally 
 difappeared. The application of the ointment with the hydr. 
 nit. rub. was made ufe of for three days, when the Rate of the 
 puflule remaining ftationary, it was exchanged for the ung. 
 hydr. nit . This appeared to have a more active effedt than the 
 
 former. 
 
[ 103 3 
 
 former, and in two or three days the virus feemed to be fubdued, 
 when a fimple drefiing was made ufe of; but the fore again 
 fhewing a difpofition to inflame, the ung. hydr. nit , was again 
 applied, and foon anfwered the intended purpofe efFedlually. 
 The girl after the tenth day, when, as has been obferved, fhe 
 became a little ill, fhewed not the leaf: fymptom of indifpofition. 
 She was afterwards expofed to the action of variolous matter, 
 and completely ref fled it. Sufan Phipps alfo went through a 
 fmilar trial. Conceiving thefe Cafes to be important, I have 
 given them in detail; firf, to urge the precaution of ufng fuch 
 means as may flop the progrefs of the puftule; and fecondly, 
 to point out (what appears to be the fadl) that the moil material 
 indifpoftion, or at leaf that which is felt moft fenfibly, does not 
 arife primarily from the firfi adlion of the virus on the confitu - 
 tion y hut that it often comes on , if the puftule is left to chance , 
 as a fecondary difeafe. This leads me to conje&ure, what 
 experiment mult finally determine, that they who have had the 
 Small Pox are not afterwards fufceptible of the primary adlion of 
 the Cow Pox virus; for feeing that the fimple virus itfelf when 
 it has not palled beyond the boundary of a veficle, excites in the 
 
 2 fyftem 
 
[ 10 4 ] 
 
 fyftem fo little commotion, is it not probable the trifling 
 illnefs thus induced may be loft in that which fo quickly, and 
 oftentimes fo feverely, follows in the cafual Cow Pox from the 
 prefence of corroding ulcers ? This confideration induces me to 
 fuppofe that I may have been miftaken in my former obfervation 
 on this fubjed. 
 
 In this refpeCt, as well as many others, a parallel may be 
 drawn between this difeafe and the Small Pox. In the latter, 
 the patient firft feels the effed of what is called the abforption of 
 the virus. The fymptoms then often nearly retire, when a frefli 
 attack commences different from the firft, and the illnefs keeps 
 pace with the progrefs of the puftules through their different 
 ftages of maturation, ulceration, &c. 
 
 Although the application I have mentioned in the cafe of 
 Mary Hearn proved fufficient to check the progrefs of ulceration 
 and prevent any fecondary fymptoms, yet, after the puftule has 
 duly exerted its influence, I fhould prefer the deftroying it 
 quickly and effedually to any other mode. The term cauftic to 
 
 a tender 
 
[ I0 5 3 
 
 a tender ear (and I conceive none will feel more interefied in this 
 Inquiry than the anxious guardians of a nurfery) may found 
 harfh and unpleafmg, but every folicitude that may arife on this 
 account will no longer exifl, when it is underflood that the 
 puflule in a Hate fit to be a died upon is then quite fuperficial, 
 and that it does not occupy the fpace of a filver penny*. 
 
 As a proof of the efficacy of this practice, even before the 
 virus had fully exerted itfelf on the fyflem, I fhall lay before my 
 reader the following hiftory. 
 
 By a reference to the Treatife on the Variolas Vaccinse it will 
 be feen, that in the month of April 1798, four children were 
 inoculated with the matter of Cow Pox, and that in two of 
 thefe cafes the virus on the arm was deflroyed foon after it had 
 produced a perceptible fickening. Mary James, aged feven 
 
 * I mention efcharotics for (topping the progrefs of the puflule, becaufe I 
 am acquainted with their efficacy ; probably more Ample means might anfwer 
 the purpofe quite as well, fuch as might be found among the mineral and 
 vegetable aflringents. 
 
 P . years, 
 
 m 
 
I 
 
 C 106 ] 
 
 years, one of the children alluded to, was inoculated in the 
 month of December following with frefh variolous matter, and 
 at the fame time was expofed to the effluvia of a patient affedted 
 with the Small Pox. The appearance and progrefs of the 
 infedted arm was, in every refpedt, fimilar to that which we 
 generally obferve when variolous matter has been inferted into 
 the fkin of a perfon who has not previoufly undergone either 
 the Cow Pox or the Small Pox. On the eighth day conceiving 
 there was infedtion in it, Hie was removed from her refidence 
 among thofe who had not had the Small Pox. I was now 
 anxioufly waiting the refult, conceiving from the date of the 
 girl’s arm fhe would fall fick about this time. On vifiting her 
 on the evening of the following day (the ninth) all I could 
 learn from the woman who attended her was, that fhe felt 
 fomewhat hotter than ufual during the night, but was not 
 reftlefs; and that in the morning there was the faint appearance 
 of a rafli about her wrifts. This went off in a few hours, and 
 was not at all perceptible to me on my vifit in the evening. 
 Not a fingle eruption appeared, the fkin having been repeatedly 
 and carefully examined. The inoculated arm continued to make 
 
 the 
 
[ io 7 ] 
 
 the ufual progrefs to the end, through all the Pages of inflam¬ 
 mation, maturation, and fcabbing. 
 
 c 
 
 On the eighth day, matter was taken from the arm of this 
 girl (Mary James) and inferted into the arms of her mother and 
 brother (neither of whom had had either the Small Pox or the 
 Cow Pox) the former about fifty years of age, the latter fix. 
 
 On the eighth day after the infertion, the boy felt indifpofed, 
 and continued unwell two days, when a meafles-like rafh ap¬ 
 peared on his hands and wrifts, and was thinly fcattered over 
 his arms. The day following his body was marbled over 
 with an appearance fomewhat fimilar, but he did not complain, 
 nor did he appear indifpofed. A few puftules now appeared, 
 the greater part of which went away without maturating. 
 
 On the ninth day the mother began to complain. She was a 
 little chilly and had a head-ache for two days, but no pujlule 
 appeared on the Jkin , nor had fhe any appearance of a rafh. 
 
 P 2 
 
 The 
 
[ io8 ] 
 
 The family was attended by an elderly woman as a nurfe, who 
 in her infancy had been expofed to the contagion of the Small 
 Pox, but had refilled it. This woman was now infedted, but 
 had the difeafe in the flighted manner, a very few eruptions 
 appearing, two or three of which only maturated. 
 
 From a folitary inffance like that adduced of Mary James, 
 
 whofe conflitution appears to have refilled the adtion of the 
 
 variolous virus, after the influence of the Cow Pox virus had 
 
 been fo foon arrefled in its progrefs, no pofitive conclufion can 
 
 * 
 
 be fairly drawn; nor from the hiflory of the three other patients 
 who were fubfequently infedled, but neverthelefs, the fadls. 
 colledtively may be deemed interefling. 
 
 That one mild variety of the Small Pox has appeared, I have 
 already plainly fhewn*; and by the means now mentioned we 
 probably may have it in our power to produce at will another. 
 
 At the time when the puflule was deflroyed in the arm of 
 
 *■ See Inquiry into the Caufes and EfFedts of the Variolas Vaccinas, page 49. 
 
 Mary 
 
[ 10 9 ] 
 
 Mary James, I was informed fhe had been indifpofed about 
 twelve hours; but I am now affured by thofe who were with 
 her, that the fpace of time was much lefs. Be that as it may, 
 in Cafes of Cow r Pox inoculation, I would not recommend any 
 application to fubdue the addon of the pudule until convincing- 
 proofs had appeared of the patient’s having felt its effeds at lead: 
 twelve hours. No harm indeed could enfue were a longer 
 period to elapfe before the application was made ufe of. In 
 fhort, it fliould be differed to have as full an effed as it could, 
 confidently with the date of the arm. 
 
 As the cafes of inoculation multiply, I am more and more 
 convinced of the extreme mildnefs of the fymptoms arifing 
 merely from the primary adion of the virus on the condituion, 
 and that thofe fymptoms which (as in the accidental Cow Pox) 
 affed the patient with feverity, are entirely fecondary, excited 
 by the irritating proceffes of inflammation and ulceration; and 
 it appears to me that this lingular virus podedes an irritating 
 quality of a peculiar kind, but as a dngle Cow Pox pudule is 
 
 all 
 
 o 
 
E no ] 
 
 all that is neceflary to render the variolous virus ineffectual, and 
 as we poffefs the means of allaying the irritation, fhould any 
 
 I 
 
 arife, it becomes of little or no confequence. 
 
 It appears then (as far as an inference can be drawn from the 
 prefent progrefs of Cow Pox inoculation) that it is an accidental 
 circumftance only, which can render this a violent difeafe, and 
 a circumftance of that nature, which fortunately it is in the 
 power of almoft every one to avoid. I allude to the commu¬ 
 nication of the difeafe from cows. In this cafe, fhould the hands 
 of the milker be affedted with little accidental fores to any 
 extent, every fore would become the nidus of infection, and feel 
 the influence of the virus; and the degree of violence in the 
 conflitutional fymptoms would be in proportion to the number 
 
 and to the flate of thefe local affections. Hence it follows that a 
 
 * * ' ■ / 
 
 perfon, either by accident or defign, might be fo filled with 
 thefe wounds from contact with the virus, that the conftitution 
 might link under the preffure. 
 
 \ .■' * ’ r ' : l. -i 
 
 Seeing 
 
[ 111 ] 
 
 Seeing that we poflefs the means of rendering the aCtion of the 
 fores mild, which, when left to chance, are capable of pro¬ 
 ducing violent effects ; and feeing too that thefe fores bear a 
 refemblance to the Small Pox, efpecially the confluent, fliould it 
 
 t 
 
 not encourage the hope that fome topical application might be 
 
 ufed with advantage to counteract the fatal tendency of that 
 difeafe, when it appears in this terrific form ? At what fiage or 
 ftages of the difeafe this may be done with the mo ft promifing 
 expectation of fuccefs, I will not pretend now to determine. I 
 only throw out this idea as the balls of further reafoning and 
 experiment. 
 
 I have often been foiled in my endeavours to communicate the 
 Cow Pox by inoculation. An inflammation will fometimes 
 fucceed the fcratch or punCture, and in a few days difappear 
 without producing any further effeCt. Sometimes it will even 
 produce an ichorus fluid, and yet the fyftem will not be a 
 feCted. The fame thing we know happens with the Small Pox 
 virus. 
 
 Four 
 
 2 
 
[ U2 ] 
 
 Four or five fervants were inoculated at a farm contiguous to 
 this place, laid fummcr, with matter juft taken from an infe&ed 
 cow. A little inflammation appeared on all their arms, but 
 died away without producing a puftule ; yet all thefe fervants 
 caught the difeafe within a month afterwards from milking the 
 infebted cows, and fome of them had it feverely. At prefent, 
 no other mode than that commonly pradtifed for inoculating the 
 Small Pox has been ufed for giving the Cow Pox ; but it is 
 probable this might be varied with advantage. We fhould 
 imitate the cafual communication more clearly were we firft, by 
 making the fmalleft fuperficial incilion or pundture on the Ikin, 
 to produce a little fcab 3 and then, removing it, to touch the 
 abraded part with the virus. A fmall portion of a thread im¬ 
 brued in the virus (as in the old method of inoculating the 
 
 * ^ 
 
 Small Pox) and laid upon the flightly incifed fkin, might pro¬ 
 bably prove a fuccefsful way of giving the difeafe; or the cutis 
 might be expofed in a minute point by an atom of bliftering 
 plafter, and the virus brought in contact with it. In the Cafes 
 juft alluded to, where I did not fucceed in giving the difeafe 
 
 conftitutionally, 
 
 J ■ 
 
 / 
 
[ u 3 ] 
 
 conftitutionally, the experiment was made with matter taken in 
 a purulent ftate from a puftule on the nipple of a cow*. 
 
 Is pure pus, though contained in a Small Pox puftule, ever 
 capable of producing the Small Pox perfectly ? I fufpect it is 
 Hot.—Let us confider that it is always preceded by the limpid 
 fluid, which, in conftitutions fufceptible of variolous con¬ 
 tagion, is always infe&ious; and though on opening a puftule 
 its contents may appear perfectly purulent, yet a given quantity 
 of the limpid fluid may at the fame time be blended with it, 
 though it would be imperceptible to the only teft of our fenfes, 
 
 the eye. The prefence then of this fluid, or its mechanical dif- 
 
 / 
 
 fuflon through pus, may at all times render adtive, what is ap¬ 
 parently mere pus , while its total abfence (as in ftale puftules) 
 may be attended with the imperfedt effedts we have feen. 
 
 It would be digrefling too widely to go far into the dodtrinc 
 
 * Since this was written, I have fcarcely ever found the virus fail to infect 
 when taken in its limpid Hate from the inoculated puftule, and inferted imme¬ 
 diately. 
 
 CL 
 
 of 
 
t 114 ] 
 
 of fecretion, but as it will not be quite extraneous, I fhall juff 
 obferve, that I coniider both the pus and the limpid fluid of 
 the puftule as fecretions, but that the organs eftabiifhed by 
 nature to perform the office of fecreting thefe fluids may differ 
 effentrally in their mechanical ftructure. What but a difference 
 in the organization of glandular bodies, conftitutes the difference 
 in the qualities of the fluids fecreted ? From fome peculiar 
 derangement hi the ftrudlure, or, in other words, fome deviation 
 fn the natural addon of a gland deftined to fecrete a mild, 
 innoxious fluid, a poifon of the moft deadly nature may be 
 created: for example-—That gland, which in its found ftate 
 fecretes pure faliva, may, from being thrown into difeafed 
 addon, produce a poifon of the moft deftruddve quality. 
 Nature appears to have no more difficulty in forming minute 
 glands among the vafcular parts of the body, than (he has in 
 forming blood veffels, and millions of thefe can be called 
 into exiftence, when inflammation is excited, in a few hours*. 
 
 * Mr. Home, in his excellent diflertation on pus and mucus, juftifies this 
 aflertion. 
 
 In 
 
.[ 1 *5 3 
 
 In the prefent early flage of the Inquiry (for early it certainly 
 muff be deemed] before we know for an abfolute certainty 
 how foon the virus of the Cow Pox may fuffer a change in its 
 fpecific properties, after it has quitted the limpid ffate it poffeffes 
 when forming a puftule, it would be prudent for thofe who 
 have been inoculated with it to fubmit to variolous inoculation. 
 No injury or inconvenience can accrue from this ; and were the 
 fame method pradtifed among thofe, who, from inoculation 
 have felt the Small Pox in an unfatisfadtory manner at any 
 period of their lives, it might appear that I had not been too 
 
 A 
 
 officious in offering a cautionary hint in recommending a fecond 
 inoculation with matter in its moil perfedt ffate. 
 
 t 
 
 And here let me fuppofe for argument’s fake (not from con- 
 vidtion) that one perfon in an hundred after having had the 
 Cow Pox fhould be found fufceptible of the Small Pox, would 
 this invalidate the Utility of the pradtice ? For, waving all other 
 coniiderations, who will deny that the inoculated Small Pox, 
 although abffradtedly it may be confdered as harmlefs, does 
 
 Qj2 not 
 
[ n6 ] 
 
 not involve in itfelf fomething that in numberlefs instances 
 proves baneful to the human frame. 
 
 That in delicate conftitutions it fometimes excites fcrofula, is 
 a fad that muft generally be fubfcribed to, as it is fo obvious to 
 common converfation. This confideration is important. 
 
 As the effeds of the Small Pox inoculation on thofe who 
 have had the Cow Pox will be watched with the molt fcrupulous 
 eye by thofe who profecute this Inquiry ; it may be proper to 
 bring to their recolledion fome fads relative to the Small Pox, 
 which I muft conlider here as of confequence, but which 
 hitherto fetm not to have made a due impreflion. 
 
 It fhould be remembered that the conflitution cannot by pre¬ 
 vious infedion be rendered totally unfufceptible of the variolous 
 poifon, neither the cafual nor the inoculated Small Pox, whether 
 it produces the difeafe in a mild or in a violent way, can per- 
 fedly extinguifh the fufceptibility. The ikin, we know, is 
 
 ever 
 
 3 
 
I **7 ] 
 
 ever ready to exhibit, though often in a very limited degree, the 
 effe&s of the poifon when inferted there; and how frequently 
 do we fee among nurfes, when much expofed to the contagion, 
 eruptions, and thefe fometimes preceded by fenfible illnefs! 
 yet fhould any thing like an eruption appear, or the fmalleft 
 degree of indifpofition, upon the infertion of the variolous 
 matter on thofe who have gone through the Cow Pox, my af- 
 fertions refpedting the peculiarities of the difeafe might be 
 unjuftly difcredited. 
 
 I know a gentleman, who many years ago was inoculated for 
 the Small Pox, but having no puftules, or fcarcely any confti- 
 tutional affedtion that was perceptible, he was diflatisfied, and 
 has fince been repeatedly inoculated. A velicle has always been 
 produced in the arm in confequence, with axillary fwelling and 
 a flight indifpofition : this is by no means a rare occurrence. It 
 is probable that the fluid thus excited upon the {kin, would 
 always produce the Small Pox. 
 
 On the arm of a perfon who had gone through the Cow Pox 
 
 many 
 
[ ] 
 
 many years before, I once produced a vefication by the infer- 
 tion of variolous matter, and with a little of the fluid, inoculated 
 a young woman who had a mild, but very efficacious Small 
 Pox in confequence, although no conftitutional effed was pro¬ 
 duced on the patient from whom the matter was taken. The 
 following communication from Mr. Fewfter affords a dill 
 clearer elucidation of this fad.—Mr. Fewfter fays, “ On the 
 
 3d of April 1797, I inoculated Mafter H—-, aged fourteen 
 
 months, for the Small Pox. At the ufual time he fickened, 
 had a plentiful eruption, particularly on his face, and got well. 
 His nurfemaid, aged twenty-four, had many years before gone 
 through the Small Pox, in the natural way, which was evident 
 from her being much pitted with it. She had ufed the child to 
 deep on her left arm, with her left cheek in contad with his 
 face, and during his inoculation he had moftly flept in that 
 manner. About a week after the child got well, fhe '(the 
 nurfe) deftred me to look at her face, which fire faid was very 
 painful. There was a plentiful eruption on the left cheek, but 
 not on any other part of the body , which went on to matura¬ 
 tion. 
 
 On 
 
E i’9 ] 
 
 “ On inquiry I found that three days before the appearance of 
 the eruption, fhe was taken with flight chilly fits, pain in her 
 head and limbs, and fome fever. On the appearance of the 
 eruption thefe pains went off, and now, (the fecond day of the 
 eruption) fhe complains of a little fore throat. Whether the 
 above fymptoms are the effects of the Small Pox or a recent cold, 
 I do not know. On the fifth day of the eruption I charged a 
 lancet from two of the puflules, and on the next day I inoculated 
 two children, one two years, the other four months old, with 
 the matter, At the fame time I inoculated, the mother and 
 eldett fitter with variolous matter taken from Matter H——. 
 On the fifth day of their inoculation all their arms were in¬ 
 flamed alike; and on the eighth day, the eldett of thofe ino¬ 
 culated from the nurfe fickened, and the youngefl on the 
 eleventh. They had both a plentiful eruption, from which I 
 inoculated feveral others, who had the difeafe very favourably* 
 The mother and the other child fickened about the fame time, 
 and likewife had a plentiful eruption. 
 
 “ Soon after a man in the village fickened with the Small 
 
 Pox,,, 
 
C 120 ] 
 
 Pox, and had a confluent kind. To be convinced that the 
 children had had the difeafe effectually, I took them to his houfe 
 and inoculated them in both arms with matter taken from him, 
 but without effeCt.” 
 
 Thefe are not brought forward as uncommon occurrences, but 
 as exemplifications of the human fyffem’s fufceptibility of the 
 variolous contagion, although it has been previoufly fenfible of 
 its aCtion. 
 
 Happy is it for mankind that the appearance of the Small Pox 
 4 fecond time on the fame perfon beyond a trivial extent, is fo 
 extremely rare, that it is looked upon as a phoenomenon. In¬ 
 deed, fince the publication of Dr. Heberden’s paper on the 
 Varicella or Chicken Pox, the idea of fuch an occurrence, m 
 deference to authority fo truly refpeCtable, has been generally 
 relinquifhed. This I conceive has been without juft reafon; for 
 after we have feen, among many others, fo ffrong a Cafe as 
 that recorded by Mr. Edward Withers, Surgeon, of Newbury, 
 Berks, in the Fourth Volume of the Memoirs of the Medical 
 
 Society 
 
[ 121 ] 
 
 
 X 
 
 . .>*4 
 
 Society of London (from which I take the following Extracts) 
 ho one I think will again doubt the fadt. 
 
 “ Mr. RICHARD LANGFORD, a farmer of Weft Shef- 
 ford, in this county (Berks) about fifty years of age, when 
 about a month old had the Small Pox at a time when three others 
 of the family had the fame difeafe, one of whom, a fervant man, 
 died of it. Mr. Langford’s countenance was ftrongly indicative 
 
 of the malignity of the diftemper, his face being fo remarkably 
 
 / 
 
 pitted and feamed as to attrack the notice of all who faw him, 
 fo that no one could entertain a doubt of his having had that 
 
 difeafe in a moft inveterate manner.” Mr. Withers proceeds to 
 ftate that Mr. Langford was feized a fecond time, had a bad 
 confluent Small Pox, and died on the twenty-firft day from the 
 feizure: and that four of the family, as alfo a fifter of the pa¬ 
 tients’, to whom the difeafe was conveyed by her fon’s vifiting 
 his uncle, falling down with the Small Pox, fully fatisfied the 
 country with regard to the nature of the difeafe, which nothing 
 ftiort of this would have done -ithe fifter died. 
 
 R 
 
 This 
 
[ 122 '] 
 
 “ This cafe was thought fo extraordinary a one, as to induce 
 the redlor of the parilh to record the particulars in the parilh 
 
 regiller. J> 
 
 It is lingular that in moll cafes of this kind, the difeafe in 
 the firft jnllance has been confluent; fo that the extent of the 
 ulceration on the Ikin (as in the Cow Pox) is not the procefs in 
 nature which affords fecurity to the conlfitution. 
 
 As the fubjedt of the Small Pox is fo interwoven with that 
 which is the more immediate objedt of my prefent concern, it 
 mull plead my excufe for fo often introducing it. At prefent it 
 mull be conlidered as a dillemper not well underllood. The 
 Inquiry I have inllituted into the nature of the Cow Pox, will 
 probably promote its more perfedt invelligation. 
 
 The Inquiry of Dr. Pearfon into the Hillory of the Cow Pox 
 having produced fo great a number of attellations in favour of 
 
 4 
 
 my affertion that it proves a protection to the human body from 
 the Small Pox, I have not been afliduous in feeking for more; 
 
 but 
 
r 123 ] 
 
 but as fome of my friends have been fo good as to communicate 
 the following, I fhall conclude thefe obfervations with their 
 infertion. 
 
 » 
 
 Extra# of a Letter from Mr. Darke, Surgeon, at Stroud, in 
 this county, and late Surgeon to the North Gloucefter Regiment 
 of Militia. 
 
 ✓ 
 
 “ In the fpring of the year 1796, I inoculated men, women, 
 
 1 t 
 
 and children, to the amount of about feventy. Many of the 
 men did not receive the infection, although inoculated at leaft 
 three times and kept in the fame room with thofe who actually 
 underwent the difeafe during the whole time occupied by them 
 in palling through it. Being anxious they fhould in future 
 be fecure againft it, I was very particular in my inquiries to 
 find out whether they ever had previoufly had it, or at any 
 time been in the neighbourhood of people labouring under it. 
 But after all, the only fatisfactory information I could obtain 
 was, that they had had the Cow Pox. As I was then ignorant 
 of fuch a difeafe affecting the human fubje#, I flattered myfelf 
 
 R 2 • what 
 
[ 124 ] 
 
 < 
 
 what they imagined to be the Cow Pox was in reality the Small 
 Pox in a very flight degree. I mentioned the circumflance in 
 the prefence of feveral of the officers, at the faffie time expreffing 
 my doubts if it were not Small Pox, and was not a little fur- 
 prifed when I was told by the Colonel that he had frequently 
 heard you mention the Cow Pox as a difeafe endemial to 
 Gloucefterfliire, and that if a perfon were ever affedxd by it, you 
 fuppofed him afterwards fecure from the Small Pox. This 
 excited my curioflty, and when I vifited Gloucefterfliire I was 
 very inquifitive concerning the fubjedl, and from the informa¬ 
 tion I have ftnce received, both from your publication and from 
 converfation with medical men of the greateft accuracy in their 
 obfervations, I am fully convinced that what the men fuppofed 
 to be the Cow Pox was a&ually fo, and I can fafely affirm that 
 they effectually refilled the Small Pox.’* 
 
 Mr. Fry, Surgeon, at Durfley in this county, favours me 
 with the following communication : 
 
 “ During the fpring of the year 1797, I inoculated fourteen 
 
 hundred 
 
[ 125 3 
 
 hundred and feventy-five patients, of all ages, from a fortnight 
 old to feventy years ; amongft whom there were many who had 
 previoufly gone through the Cow Pox. The exadl number I 
 cannot fiate; but if I fay they were near thirty, I am certainly 
 
 t 
 
 within the number. There was not a fingle infiance of the 
 variolous matter producing any confiitutional effect on thefe 
 people, nor any greater degree of local inflammation than it 
 would have done in the arm of a perfon who had before gone 
 through the Small Pox, notwithftanding it was invariably 
 inferted four, flve, and fometimes fix different times, to fatisfy 
 the minds of the patients. In the common courfe of inoculation 
 previous to the general one, fcarcely a year pafled without my 
 meeting with one or two infiances of perfons who had gone 
 through the Cow Pox, refilling the adlion of the variolous con¬ 
 tagion. I may fairly fay, that the number of people I have feen 
 inoculated with the Small Pox, who at former periods had gone 
 through the Cow Pox, are not lefs than forty; and in no one 
 infiance have I known a patient receive the Small Pox, notwitfi- 
 Handing they invariably continued to aflbeiate with other inocu¬ 
 lated patients during the progrefs of the difeafe, and many of 
 
 them 
 
[ 126 3 
 
 them purpofely expofed themfelves to the contagion of the natural 
 Small Pox ; whence I am fully convinced, that a perfon who 
 had fairly had the Cow Pox, is no longer capable of being 
 adted upon by the variolous matter. 
 
 “ I alfo inoculated a very confiderable number of thofe who 
 had had a difeafe which ran through the neighbourhood a few 
 years ago, and was called by the common people the Swine Pox, 
 not one of whom received the Small Pox*. 
 
 “ There w r ere about half a dozen inftances of people who 
 never had either the Cow or Swine Pox, yet did not receive the 
 Small Pox, the fyftem not being in the lead: deranged, or the 
 arms inflamed, although they were repeatedly inoculated, and 
 affociated with others who were labouring under the difeafe; 
 one of them was the fon of a farrier.” 
 
 * I his was that mild variety of the Small Pox which I have noticed in the 
 late Treadfe on the Cow Pox, page 49. 
 
 Mr. 
 
[ 127 ] 
 
 Mr. Tierny, Afliflant Surgeon of the South Gloucefler Regi¬ 
 ment of Militia, has obliged me with the following informa¬ 
 tion : 
 
 “ That in the fummer of the year 1798, he inoculated a great 
 number of the men belonging to the Regiment, and that among 
 them he found eleven, who, from having lived in dairies, had 
 gone through the Cow Pox. That all of them refitted the 
 Small Pox, except one, but that on making the mott rigid and 
 fcrupulous inquiry at the farm in Glouceflerlhire, where the man 
 faid he lived when he had the difeafe, and among thofe with 
 whom at the fame time he declared he had aflociated, and parti- 
 cularly of a perfon in the parifh, whom he faid had dretted his 
 fingers, it mott clearly appeared that he aimed at an impofition, 
 and that he never had been attested with the Cow Pox*. Mr. 
 Tierny remarks, that the arms of many who were inoculated 
 after having had the Cow Pox inflamed very quickly, and that 
 in feveral a little ichorus fluid was formed.” 
 
 * The public cannot be too much upon their guard rcfpe£ling perfons of this 
 
 defcription. 
 
 Mr. 
 
[ 128 ] 
 
 Mr. Cline, who in July laft was fo obliging at my requeft as 
 to try the efficacy of the Cow Pox vims, was kind enough to 
 give me a letter on the refult of it, from which the following is 
 an extract: 
 
 “ My Dear Sir, 
 
 <c The Cow Pox experiment has fucceeded admirably. The 
 child fickened on the feventh day, and the fever, which was 
 moderate, fubfided on the eleventh. The inflammation arifing 
 from the infertion of the virus extended to about four inches in 
 diameter, and then gradually fubfided, without having been 
 attended with pain or other inconvenience. There were no 
 eruptions. 
 
 “ I have fince inoculated him with Small Pox matter in three 
 
 places, which were flightly inflamed on the third day, and then 
 
 / 
 
 fubfided. 
 
 “ Dr. Lifler, who was formerly Phyfician to the Small Pox 
 Hofpital, attended the child with me, and he is convinced that 
 
 2 
 
 it 
 
[ 129 j 
 
 it is not poflible to give him the Small Pox. I think the fub- 
 ftituting the Cow Pox poifon for the Small Pox, promifes to be 
 one of the greateft improvements that has ever been made in 
 medicine j and the more I think on the fubjed, the more I am 
 impreded with its importance. 
 
 “ With great edeem 
 “ I am, &c. 
 
 Lincoln’s Inn Fields, 
 
 % 
 
 Auguft 2, 1798, “ Henry Cline. 55 
 
 From communications, with which I have been favoured 
 from Dr. Pearfon, who has occasionally reported to me the 
 refult of his private pradice with the vaccine virus in London, 
 and from Dr. Woodville, who has alfo favoured me with 
 an account of his more extenlive inoculation with the fame 
 virus at the Small Pox Hofpital, it appears that many of their 
 patients have been affeded with eruptions, and that thefe erup¬ 
 tions have maturated in a manner very dmilar to the variolous. 
 The matter they made life of was taken, in the firft inftance, 
 from a cow belonging to one of the great milk farms in London. 
 
 S * Having 
 
t 130 ] 
 
 / 
 
 Having never feen maturated puftules produced either in my 
 own pra&ice among thofe who were cafually infedted by cows, 
 or thofe to whom the difeafe had been communicated by inocu- 
 lation, I was defirous of feeing the effect of the matter generated 
 in London, on fubje&s living in the country. A thread im¬ 
 brued in fome of this matter was fent to me, and with it two 
 children were inoculated, whofe Cafes I fhall tranfcribe from 
 my notes. 
 
 STEPHEN JENNER, three years and a half old. 
 
 3d day. The arm fhewed a proper and decifive inflammation. 
 
 6th. A veflcle ariflng. 
 
 7th. The puflule of a cherry colour. 
 
 8th. Increaflng in elevation.—A few fpots now appear on 
 each arm near the infertion of the inferior tendons of the biceps 
 mufcles. They are very fmall, and of a vivid red colour. The 
 pulfe natural; tongue of its natural hue ; no lofs of appetite, or 
 any fymptom of indifpofition. 
 
 9th. The inoculated puflule on the arm this evening began to 
 inflame, and gave the child uneafinefs : he cried, and pointed 
 
 to 
 
/ 
 
 [ i3i ] 
 
 to the feat of it, and was immediately afterwards affected with 
 febrile fymptoms. At the expiration of two hours after the 
 feizure, a plafter of ung. hydrarg. fort, was applied, and its 
 efredt was very quickly perceptible; for in ten minutes he 
 refumed his ufual looks and playfulnefs. On examining the 
 arm about three hours after the application of the plafter, its 
 effedts in fubduing the inflammation were very manifeft. 
 
 10th. The fpots on the arms have difappeared, but there arc 
 three viflblc in the face. 
 
 nth. Two fpots on the face are gone; the other barely per¬ 
 ceptible. ' ; 
 
 13th. The puftule delineated in the fecond plate in the 
 Treatife on the Variolas Vaccinae, is a corredt reprefentation of 
 that on the child’s arm, as it appears at this time. 
 
 14th. Two frefh fpots appear on the face. The puftule on 
 the arm nearly converted into a fcab. As long as any fluid re- 
 mained in it, it was limpid, 
 
 JAMES HILL, fouf years old, was inoculated on the fame 
 day, and with part of the fame matter which infedted Stephen 
 
 S 2 • Jenner. 
 
[ i3* 3 
 
 Jenner. It did not appear to have taken effedt till the fifth 
 day. 
 
 7th. A perceptible veficle : this evening the patient became 
 a little chilly ; no pain or tumour difcoverable in the axilla.. 
 
 8 th. Perfectly well. 
 
 9th. The fame. 
 
 10th. The veficle more elevated than I have been accuftomed 
 to fee it, and afliiming more perfectly the variolous charadter 
 than is common with the Cow Pox at this ftage. 
 
 11th. Surrounded by an inflammatory rednefs, about the 
 fize of a fhilling, fludded over with minute veficles. The 
 puflule contained a limpid fluid till the fourteenth day, after 
 w r hich it was incrufted over in the ufual manner; but this in- 
 cruflation or fcab being accidentally rubbed off, it was flow in 
 healing. 
 
 t 
 
 Thefe children were afterwards fully expofed to the Small Pox 
 contagion without effedt 
 
 Having been requefted by my friend Mr. Henry Hicks, of 
 
 Eaftington, 
 
[ 133 ] 
 
 Eaflington, in this county, to inoculate two of his children, and 
 at the fame time fome of his fervants and the people employed 
 in his manufactory, matter was taken from the arm of this boy 
 for the purpofe. The numbers inoculated were eighteen. They 
 all took the infeCtion, and either on the fifth or fixth day a 
 veficle was perceptible on the punCtured part. Some of them 
 began to feel a little unwell on the eighth day, but the greater 
 number on the ninth. Their illnefs, as in the former Caleb 
 defcribed, was of fliort duration, and not fufficient to interrupt, 
 but at very fliort intervals, the children from their amufements, 
 or the fervants and manufacturers from following their ordinary 
 bufinefs. 
 
 Three of the children, whole employments in the manufactory 
 was in fome degree laborious, had an inflammation on their 
 arms beyond the common boundary about the eleventh or 
 twelfth day, when the feverifh fymptoms, which before were 
 nearly gone off, again returned, accompanied with increafe of 
 axillary tumour. In thefe Cafes (clearly perceiving the fymp¬ 
 toms were governed by the date of the arms) I applied on the 
 
 * ' inoculated 
 
[ i34 J 
 
 f inoculated puftules, and renewed the application three or four 
 
 / 
 
 times within an hour, a pledget of lint, previoufly foaked in 
 aqua lythargyri acetati *, and covered the hot efflorefcence fur- 
 rounding them, with cloths dipped in cold water. 
 
 The next day I found this fimple mode of treatment had 
 fucceeded perfectly. The inflammation was nearly gone off. 
 and with it the fymptoms which it had produced. 
 
 Some of thefe patients have fince been inoculated with vario¬ 
 lous matter without any effedt beyond a little inflammation on 
 the part where it was inferted. , . 
 
 Why the arms of thofe inoculated with the vaccine matter 
 in the country fhould be more difpofed to inflame than thofe 
 inoculated in London, it may be difficult to determine. From 
 comparing my own Cafes with fome tranfmitted to me by Dr. 
 Pearfon and Dr. Woodville, this appears to be the fad : and 
 
 * Goulard’s Extraft of Saturn. 
 
 what 
 
[ 135 ] 
 
 what ftrikes me as hill more extraordinary with refped to thofe 
 inoculated in London is, the appearance of maturating eruptions. 
 In the two inftances only, which I have mentioned (the one 
 from the inoculated, the other from the cafual Cow Pox) a few 
 red fpots appeared, which quickly went off without maturating. 
 The Cafe of the Rev. Mr. Moore’s fervant may indeed feem 
 like a deviation from the common appearances in the country, 
 but the nature of thefe eruptions was not afcertained beyond 
 their not pofTeffing the property of communicating the difeafe by 
 their effluvia. Perhaps the difference we perceive in the Rate 
 of the arms may be owing to fome variety in the mode of 
 adion of the virus upon the fkin of thofe who breathe the air 
 of London, and thofe who live in the country. That the eryfi- 
 pelas affumes a different form in London from what we fee it 
 put on in the country, is a fad very generally acknowledged. 
 In calling the inflammation, that is- excited by the Cow Pox 
 virus, eryfipelatous, perhaps I may not be critically exad, but 
 it certainly approaches near to it. Now, as the difeafed adion 
 going forward in the part infeded with the virus may undergo 
 different modifications, according to the peculiarities of the 
 
 condi tut ion. 
 
[ 13*5 ] 
 
 conftitution on which it is to produce its effed, may it not 
 account for the variation which has been obferved ? 
 
 To this it may probably be objeded, that fame of the patients 
 inoculated, and who had pu flutes in confequence, were newly 
 come from the country j but I conceive that the changes 
 
 wrought in the human body through the medium of the lungs, 
 
 \ 
 
 may be extremely rapid. Yet, after all, further experiments 
 made in London with vaccine virus generated in the country, 
 mufi finally throw a light on what now certainly appears obfcure 
 
 and myfterious. 
 
 _ •#. 
 
 * / 
 
 The principal variation perceptible to me in the addon of the 
 vaccine virus generated in London from that produced in the 
 country, was its proving more certainly infedious and giving a 
 lefs difpofition in the arm to inflame. There appears alfo a 
 greater elevation of the puftule above the furrounding fkin. In 
 my former cafes, the puftule produced by the infertion of the 
 virus was more like one of thofe which are fo thickly fpread over 
 the body in a bad kind of confluent Small Pox. This was more 
 
 like 
 
I 137 ] 
 
 like a puftule of the diftindt Small Pox, except that I faw no 
 inftance of pus being formed in it, the matter remaining limpid 
 till the period of fcabbing. 
 
 Wilhing to fee the effects of the difeafe on an infant newly 
 born, my nephew, Mr. Henry Jenner, at my requeft, inferted 
 the vaccine virus into the arm of a child about twenty hours old. 
 His report to me is, that the child went through the difeafe 
 without apparent illnefs, yet that it was found effedtually to relift 
 the adtion of variolous matter with which it was fubfequently 
 inoculated. 
 
 / • 1 ' ' ... 
 
 I have had an opportunity of trying the effedts of the Cow 
 Pox matter on a boy, who, the day preceding its infection, 
 lickened with the mealies. The eruption of the mealies, attend¬ 
 ed with cough, a little pain in the cheft, and the ufual fymp- 
 toms accompanying that difeafe, appeared on the third day, and 
 fpread all over him. The difeafe went through its courfe with¬ 
 out any deviation from its ufual habits; and, notwithllanding 
 this, the Cow Pox virus excited its common appearances, both 
 
 r T on 
 
C 138 ] 
 
 on the arm and on the conflitution, without any fenfible inter¬ 
 ruption ; on the fixth day there was a veficle. 
 
 8th. Pain in the axilla, chilly, and affedted with head-ache. 
 
 9th. Nearly well. 
 
 12th. The puftule fpread to the fize of a large fplit pea, but 
 without any furrounding efflorefcence. It foon afterwards 
 fcabbed, and the boy recovered his general health rapidly. But 
 it fhould be obferved, that before it fcabbed, the efflorefcence, 
 which had fuffered a temporary fufpenlion advanced in the ufual 
 manner. 
 
 > 
 
 Here we fee a deviation from the ordinary habits of the Small 
 Pox, as it has been obferved that the prefence of the mealies 
 fufpends the action of variolous matter. However, the fufpen¬ 
 iion of the efflorefcence is worthy of obfervation. 
 
 The very general invelfigation that is now taking place, chiefly 
 through inoculation (and I again repeat my earned: hope that it 
 may be conducted with that calmnefs and moderation which 
 fhould ever accompany a philofophical refearch) mull foon 
 
 3 place 
 
I 
 
 [ 139 ] 
 
 place the vaccine difeafe in its juft point of view. The refult 
 of all my trials with the virus on the human fubjecft, has been 
 uniform. In every inftance, the patient who has felt its in¬ 
 fluence, has completely loft the fufceptibilitv for the variolous 
 contagion : and as thefe inftances are now become numerous, I 
 
 O' 1 
 
 conceive that, joined to the obfervations in the former part of 
 this paper, they fufflciently preclude me from the neceflity of 
 
 1 
 
 entering into controversies with thofe who have circulated 
 reports adverfe to my aflertions, on no other evidence than what 
 has been cafually collected. 
 
 T 2 
 
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A CONTINUATION OF 
 
 FACTS AND OBSERVATIONS 
 
 RELATIVE TO THE 
 
 VARIOLA vaccinal. 
 
A 
 
 CONTINUATION 
 
 OF 
 
 RELATIVE TO THE 
 
 VARIOLA VACCIN7E, 
 
 OR 
 
 COW POX, 
 
 Miii >m a. ftr>wsirrneBwfa*» 
 
 By EDWARD JENNER, M.D. F.R.S. F.L.S. &c. 
 
 lUmijon: 
 
 PRINTED, FOR THE AUTHOR, 
 
 BY SAMFSON LOW, N. 7, BERWICK STREET, SOHO : 
 
 AND SOLD BY LAW, AVE-MARIA LANE; AND MURRAY AND HIGIILEY’j FLEET STREET. 
 
 iSOO. 
 
A CONTINUATION OF 
 
 FACTS AND OBSERVATIONS, 
 
 £?c. &c. 
 
 Since my former publications on the Vaccine Inoculation, I 
 have had the fatisfadion of feeing it extend very widely. Not 
 only in this country is the fubjed purfued with ardour, but from 
 my correfpondence with many refpedable medical gentlemen 
 on the Continent, (among whom are Dr. De Carro of Vienna, 
 and Dr. Ballhorn of Hanover) I find it is as^ warmly adopted 
 abroad, where it has afforded the greateft fatisfadion. I have 
 
 the 
 
C 146 ] 
 
 the pleafure too of feeing that the feeble efforts of a few in¬ 
 dividuals to depreciate the new practice, are finking faff into 
 contempt beneath the immenfe mafs of evidence which has rifen 
 up in fupport of it. 
 
 Upwards of fix thoufand perfons have now been inoculated 
 with the virus of Cow Pox, and the far greater part of them 
 have lince been inoculated with that of Small Pox, and expofed 
 to its infe&ion in every rational way that could be devifed, with¬ 
 out effedt. 
 
 It was very improbable that the invefligation of a difeafe fo 
 analagous to the Small Pox, fhould go forward without engaging 
 the attention of the Phyfician of the Small Pox Hofpital in 
 London. 
 
 Accordingly, Dr. Woodville, who fills that department with 
 fo much refpedtability, took an early opportunity of militating 
 an Inquiry into the nature of the Cow Pox. This Inquiry was 
 began in the early part of the prefent year, and in May, Dr. 
 
 2 Woodville 
 
[ 147 ] 
 
 Woodville publifhed the refult, which differs effentially from 
 mine in a point of much importance. It appears that three-fifths 
 of the patients inoculated were affed:ed with eruptions, for the 
 moil part fo perfectly refembling the Small Pox, as not to be 
 diftinguifhed from them. On this fubjedt it is neceffary that 
 I fhould make fome comments. 
 
 When I confider that out of the great number of Cafes of 
 cafual inoculation immediately from cows, which have from 
 time to time prefented themfelves to my obfervation, and the 
 many fimilar inftances which have been communicated to me 
 by medical gentlemen in this neighbourhood ; when I con¬ 
 fider too that the matter with which my inoculations were 
 conducted in the years 1797, 98, and 99, was taken from 
 different cows, and that in no inftance any thing like a vario¬ 
 lous puftule appeared, I cannot feel difpofed to imagine that 
 eruptions, fimilar to thofe defcribed by Dr. Woodville, have 
 ever been produced by the pure uncontaminated Cow Pock 
 virus: on the contrary, I do fuppofe that thofe which the 
 
 Doctor fpeaks of, originated in the adtion of variolous matter, 
 
 % 
 
 which 
 
[ 148 ] 
 
 which crept into the conftitution with the vaccine. And this 
 I prefume happened from the inoculation of a great number of the 
 patients with variolous matter (fome on the third, others on the 
 fifth day) after the vaccine had been applied; and it fhould be 
 obferved, that the matter thus propagated became the fource of 
 future inoculations in the hands of many medical gentlemen 
 who appeared to have been previoufly unacquainted with the 
 nature of the Cow Pox. 
 
 Another circumftance ftrongly, in my opinion, fupporting 
 this fuppofition, is the following : The Cow Pox has been 
 known among our dairies time immemorial. If puftules then, 
 like the variolous, were to follow the communication of it 
 from the cow to the milker, would not fuch a fadt have been 
 known, and recorded at our farms ? Yet, neither our farmers 
 nor the medical people of the neighbourhood have noticed fuch 
 an occurrence. 
 
 A few fcattered pimples I have fometimes, though very rarely 
 feen, the greater part of which have generally difappeared 
 
 quickly, 
 
 i 
 
C 149 3 
 
 quickly, but fome have remained long enough to fuppurate at 
 their apex. That local cuticular inflammation, whether fpring- 
 ing up fpontaneoufly, or ariflng from the application of acrid 
 fubftances, fuch, for inftance, as Cantharides , Fix Burgundica, 
 Antimonium Tartarizatum , &c. will often produce cutaneous 
 affedions, not only near the feat of the inflammation, but on fome 
 parts of the (kin far beyond its boundary, is a well-known fad:. 
 It is, doubtlefs, on this principle that the inoculated Cow-pock 
 puftule and its concomitant efflorefcence may in very irritable 
 conftitutions produce this affedion. The eruption I allude to, 
 has commonly appeared fome time in the third week after 
 inoculation. But this appearance is too trivial to excite the 
 leaf! regard. 
 
 The change which took place in the general appearance 
 during the progrefs of the vaccine inoculation at the Small Pox 
 Hofpital fhould likewife be confldered. 
 
 \ 
 
 Although at firfl: it took on fo much of the variolous charader 
 as to produce puftules in three Cafes out of five, yet in Dr. 
 
 X Woodville*s 
 
[ * 5 ° ] 
 
 Woodville’s laft report, publifhed in June, he fays, “ fince the 
 
 i 
 
 publication of my reports of inoculations for the Cow Pox, 
 upwards of three hundred Cafes have been under my care ; and 
 out of this number, only thirty-nine had puftules that fup- 
 purated : viz. out of the firft hundred, nineteen had puftules ; 
 out of the fecond, thirteen; and out of the laft hundred and 
 ten, only feven had puftules. Thus it appears that the difeafe 
 has become conftderably milder; which I am inclined to at¬ 
 tribute to a greater caution ufed in the choice of the matter, 
 with which the infection was communicated; for lately, that 
 which has been employed for this purpofe has been taken only 
 from thofe patients in whom the Cow Pox proved very mild 
 and well charaCterifed*,” 
 
 The inference I am induced to draw from thefe premifes is very 
 different. The decline, and finally, the total extinction nearly of 
 
 * In a few weeks after the Cow Pox inoculation was introduced at the Small 
 Pox Hofpital, I was favoured with fome virus from this Hock. In the firft 
 inflance it produced a few puftules, which did not maturate ; but in the fubfe- 
 quent cafes none appeared. E. J. 
 
 puftules, 
 
[ 151 3 
 
 thefe puflules, in my opinion, are more fairly attributable to the 
 Cow Pox virus, affimilating the variolous*, the former probably 
 being the original, the latter the fame difeafe under a peculiar, 
 and at prefent an inexplicable modification. 
 
 One experiment tending to elucidate the point under difcufhon, 
 I had myfelf an opportunity of inftituting. On the fuppofition 
 of its being pollible that the Cow which ranges over the fertile 
 meadows in the vale of Gloucefter, might generate a virus 
 differing in fome refpedts in its qualities from that produced by 
 the animal artificially pampered for the production of milk for 
 the metropolis, I procured, during my refidence there in the 
 fpring, fome Cow Pock virus from a cow at one of the London 
 milk-farms-f. It was immediately conveyed into Gloucefter- 
 
 * In my firft publication on this fubjedt, I expreffed an opinion that the Small 
 Pox and the Cow Pox were the fame difeafes under different modifications. In 
 this opinion Dr. Woodville has concurred. The axiom of the immortal Hauter, 
 that two difeafed actions cannot take place at the Janie time in one and the fame part, 
 will not be injured by the admiifion of this theory. 
 
 t It was taken by Mr. Tanner, then a fludent at the Veterinary College, from 
 a cow at Mr. Clark’s farm at Kentifh Town. 
 
 X 2- 
 
 fhire 
 
C J 52 3 
 
 s 
 
 fhire to Dr. Marfhall, who was then extenfively engaged in the 
 inoculation of the Cow Pox, the general refult of which, and 
 of the inoculation in particular with this matter, I £hall lay 
 before my Readers in the following communication from the 
 Dodtor. 
 
 “ Dear Sir, ; > ’ i 
 
 “ My neighbour Mr. Hicks having mentioned your wifh 
 to be informed of the progrefs of the inoculation here for the 
 Cow Pox, and he alfo having taken the trouble to tranfmit to 
 you my minutes of the Cafes which have fallen under my care, 
 I hope you will pardon the further trouble I now give you in 
 Rating the obfervations I have made upon the fubjedt. When firft 
 informed of it, having two children who had not had the Small. 
 Pox, I determined to inoculate them for the Cow Pox when¬ 
 ever I fhould be fo fortunate as to procure matter proper for the 
 purpofe. I was therefore particularly happy when I was in¬ 
 formed that I could procure matter from fome of thofe whom 
 you had inoculated. In the firft inftance, I had no intention 
 of extending the difeafe further than my own family, but the 
 
 3 very 
 
[ 1 53 3 
 
 V 
 
 very ex ten five influence which the convi&ion of its efficacy 
 
 i 
 
 in refitting the Small Pox has had upon the minds of the people 
 in general, has rendered that intention nugatory, as you will 
 perceive by the continuation of my Cafes enclofed in this 
 letter*, by which it will appear, that fince the 22d of March, 
 I have inoculated an hundred and feven perfons ; which, con- 
 fidering the retired fituation I refide in, is a very great number. 
 There are alfo other confiderations which, befides that of its 
 influence in refitting the Small Pox, appear to have had their 
 weight; namely, the peculiar mildnefs of the difeafe, the 
 known fafety of it, and its not having in any inttance prevented 
 the patient from following his ordinary bufinefs. In all the 
 Cafes under my care, there have only occurred two or three 
 which required any application owing to eryfipelatous inflam¬ 
 mation on the arm, and they immediately yielded to it. In the 
 remainder the conftitutional illnefs has been flight but fufficiently 
 parked, and confiderably lefs than I ever obferved in the fame 
 
 * Do6tcr Marfhall has detailed thefe Cafes with great accuracy, but their 
 
 publication would now be deemed fuperfluous. 
 
 E.J, 
 
 number 
 
E i54 1 
 
 number inoculated with the Small Pox. In only one or two of 
 the Cafes have any; other eruptions appeared than thofe around 
 the fpot where the matter was inferted, and thofe near the 
 infected part. Neither does there appear in the Cow Pox to be 
 the leaft exciting caufe to any other difeafe, which in the Small 
 Pox has been frequently obferved, the conftitution remaining 
 in as full health and vigour after the termination of the difeafe as 
 before the infection. Another important confideration appears 
 to be the impoilibility of the difeafe being communicated except 
 by the adtual contadt of the matter of the puflule, and confe- 
 quently the perfect fafety of the remaining part of the family, 
 fuppofing only one or two fhould wifh to be inoculated at the 
 fame time. 
 
 “ Upon the whole it appears evident to me, that the Cow 
 Pox is a pleafanter, fhorter, and infinitely more fafe difeafe 
 than the inoculated Small Pox when conduced in the mofl: 
 careful and approved manner; neither is the local affedfion of 
 the inoculated part, or the conflitutional illnefs near fo violent. 
 
 I fpeak with confidence on the fubjedt, having had an oppor- 
 
 / ■ 
 
 tunity 
 
 ■ 
 
 
E 1 55 J 
 
 tunity of obferving its effedts upon a variety of conftitutions, 
 from three months old to fixty years ; and to which I have paid 
 particular attention. In the Cafes alluded to here, you will 
 obferve that the removal from the original fource of the matter 
 has made no alteration or change in the nature or appearance of 
 the difeafe, and that it may be continued, ad infinitum, (I 
 imagine) from one perfon to another (if care be obferved in 
 taking the matter at a proper period) without any neceffity of 
 recurring to the original matter of the cow. 
 
 “ I fhould be happy if any endeavours of mine could tend 
 further to elucidate the fubjedt, and fliall be much gratified in 
 fending you any further obfervations I may be enabled to make,. 
 
 “ I have the pleafure to fubfcribe myfelf, 
 
 “ Dear Sir, &c. 
 
 Eaftington, Gloucefterfhire, 
 
 April26th, 1799. “Joseph H, Marshall. 53 
 
 The gentleman who favoured me with the above account, has 
 continued to profecute his inquiries with unremitting induftry, 
 
 and 
 
 1 
 
E *56 3 
 
 and has communicated the refult in another letter, which at his 
 requefb I lay before the public without abbreviation. 
 
 Dr. MARSHALL’S SECOND LETTER. 
 
 Dear Sir, 
 
 “ Since the date of my former letter, I have continued to 
 inoculate with the Cow Pox virus. Including the cafes before 
 enumerated, the number now amounts to four hundred and 
 twenty-three. It would be tedious and ufelefs to detail the 
 progrefs of the difeafe in each individual—it is fufficient to 
 obferve, that I noticed no deviation in any refpedt from the 
 Cafes I formerly adduced. The general appearances of the arm 
 exadtly correfponded with the account given in your firft 
 publication. When thev were difpofed to become troublefome 
 by eryflpelatous inflammation, an application of equal parts of 
 vinegar and water always anfwered the defired intention. I 
 
 muft not omit to inform you that when the difeafe had duly 
 
 1 • \ 
 
 a died upon the confldtution, I have frequently ufed the vitriolic 
 acid. A portion of a drop applied with the head of a probe or 
 
 any 
 
C *57 ]. 
 
 any convenient utenfil upon the puflule, fuffered to remain 
 about forty feconds, and afterwards wafhed off with fponge and 
 water, never failed to flop its progrefs, and expedite the for¬ 
 mation of a fcab. 
 
 y • 
 
 “ I have already fubjedted two hundred and eleven of my 
 patients to the adtion of variolous matter, but every one re - 
 fjled it. 
 
 “ The refult of my experiments (which were made with, 
 every requifite caution) has fully convinced me that the true 
 Cow Pox is a fafe and infallible preventive from the Small Pox ; 
 that in no cafe which has fallen under my obfervation has it 
 been in any confiderable degree troublefome, much lefs have I 
 feen any thing like danger ; for in no inftance were the patients 
 prevented from following their ordinary employments. 
 
 “ In Dr. Woodville’s publication on the Cow Pox, 1 notice an 
 extraordinary fadt. He fays that the generality of his patients 
 had puftules. It certainly appears extremely extraordinary that 
 
 Y 
 
 m 
 
f 
 
 \ ' 
 
 [ 158 ] 
 
 in all my Cafes there never was but one puftule, which appeared 
 on a patient’s elbow on the inoculated arm, and maturated. It 
 appeared exactly like that on the incifed part. 
 
 “ The whole of my obfervations, founded as it appears on an 
 extenfive experience, leads me to thefe obvious conclufions; 
 
 1 
 
 that thofe Cafes which have been or may be adduced againft 
 the preventive powers of the Cow Pox, could not have been 
 thofe of the true kind, fince it muft appear to be abfolutely 
 impoftible that I fhould have fucceeded in fuch a number of 
 Cafes without a fingle exception, if fuch a preventive power did 
 not exift. I cannot entertain a doubt that the inoculated Cow 
 Pox muft quickly fupercede that of Small Pox. If the many 
 important advantages which muft refult from the new pra&ice 
 are duly confidered, we may reafonably infer that public benefit, 
 the fure teft of the real merit of difcoveries, will render it 
 generally extenfive. 
 
 44 To you, Sir, as the difcoverer of this highly beneficial 
 pra&ice, mankind are under the higheft obligations. As a 
 
 private 
 
C 159 J 
 
 private individual I participate in the general feeling; more 
 particularly as you have afforded me an opportunity of noticing 
 the effects of a lingular difeafe, and of viewing the progrefs of 
 the molt curious experiment that ever was recorded in the 
 Hi dory of Phyfiology. 
 
 “ I remain, Dear Sir, &c. 
 
 C( Joseph H. Marshall. 
 
 “ P. S. I fhould have obferved, that of the patients I ino¬ 
 culated and enumerated in my letter, one hundred and twenty- 
 feven were infedted with the matter you fent me from the 
 London cow. I difcovered no diflimilarity of fymptoms in 
 thefe cafes, from thofe which I inoculated from matter procured 
 in this country. No puftules have occurred, except in one or 
 two cafes, where a fingle one appeared on the inoculated arm. 
 No difference was apparent in the local inflammation. There was 
 no fufpenfion of ordinary employment among the labouring 
 people, nor was any medicine required. 
 
 Y 2 
 
 I have 
 
c 
 
 ✓ 
 
 [ 160 ] 
 
 “ 1 have frequently inoculated one or two in a family, and 
 the remaining part of it fome weeks afterwards. The unin- 
 
 \ 
 
 felted have flept with the infected during the whole courfe of 
 the difeafe without being affedted; fo that I am fully convinced 
 that the'difeafe cannot be taken but by adtual contadt with the 
 matter. 
 
 44 A curious fadl has lately fallen under my obfervation, 
 on which I leave you to comment. 
 
 “ I viflted a patient with the confluent Small Pox, and 
 charged a lancet with fome of the matter. Two days afterwards 
 I was defired to inoculate a woman and four children with the 
 Cow Pox, and I inadvertently took the vaccine matter on the 
 
 fame lancet which was before charged with that of Small Pox. 
 
 1 ' . ; ?: 
 
 In three days I difcovered the miflake, and fully expected that 
 my five patients would be infected with Small Pox ; but I was 
 agreeably furprifed to find the difeafe to be the genuine Cow 
 Pox, which proceeded without deviating in any particular from 
 
 * 
 
 my 
 
[ 161 ] 
 
 my former cafes. I afterwards inoculated thefe patients with 
 variolous matter, but all of them re lifted its addon* 
 
 “ I omitted mentioning another great advantage that now 
 occurs to me in the inoculated Cow Pox ; I mean the fafety 
 with which pregnant women may have the difeafe communicated 
 to them. I have inoculated a great number of females in that 
 fituation, and never obferved their cafes to differ in any refped 
 from thofe of my other patients. Indeed the difeafe is fo mild, 
 that it feems as if it might at all times be communicated with 
 the mod: perfed Safety.” 
 
 v 
 
 I fhall here take the opportunity of thanking Dr. Marfhall 
 and thofe other gentlemen who have obligingly prefented me 
 with the refult of their inoculations; but, as they all agree in 
 the fame point as that given in the above communication, 
 namely, the fecurity of the patient from the effeds of the Small 
 Pox after the Cow Pox, their perufal, I prefume, would afford 
 us fatisfadion that has not been amply given already. Particular 
 occurrences I fhall of courfe detail. Some of my corres¬ 
 pondents 
 
 
[ 162 ] 
 
 pendents have mentioned the appearance of Small Pox-like 
 eruptions at the commencement of their inoculations; but in 
 thefe cafes the matter was derived from the original flock at the 
 Small Pox Hofpital. 
 
 I have myfelf inoculated a very confiderable number from the 
 matter produced by Dr. MarfhalPs patients, originating in the 
 London cow, without obferving puftules of any kind, and have 
 difperfed it among others who have ufed it with a fimilar 
 effedt. From this fource Mr. H. Jenner informs me, he has 
 inoculated above an hundred patients without obferving eruptions. 
 Whether the nature of the virus will undergo any change from 
 being farther removed from its original fource in palling fuc- 
 cefhvely from one perfon to another, time alone can determine. 
 That which I am now employing has been in ufe near eight 
 months, and not the leaf! change is perceptible in its mode of 
 adtion either locally or conflitutionally. There is therefore 
 
 every reafon to expedt that its effedls will remain unaltered, 
 
 * 
 
 and that we fhall not be under the neceffity of feeking frefh 
 
 fupplies from the cow. 
 
 The 
 
[ i6a 3 
 
 The following obfervations were obligingly lent me by Mr. 
 Tierny, Afliftant Surgeon to the South Gloucefter Regiment of 
 Militia, to whom I am indebted for a former report on this 
 fubjedt. 
 
 “ I inoculated with the Cow Pox matter from the nth to 
 the latter part of April, twenty-five perfons, including women 
 and children. Some on the 11th were inoculated with the 
 matter Mr. Shrapnell (Surgeon to the Regiment) had from you, 
 the others with matter taken from thefe. The progrefs of the 
 pun&ure was accurately obferved, and its appearance feemed to 
 differ from the Small Pox in having lefs inflammation around its 
 balls on the firft days, that is, from the third to the feventh j 
 but after this the inflammation increafed, extending on the tenth 
 or eleventh day to a circle of an inch and a half from its centre, 
 and threatening very fore arms; but this I am happy to fay was 
 not the' cafe ; for, by applying mercurial ointment to the in¬ 
 flamed part, which was repeated daily until the inflammation 
 went off, the arm got well without any further application or 
 
 trouble. 
 
[ ] 
 
 trouble. The conftitutional fymptoms which appeared on 
 the eighth or ninth day after inoculation, fcarcely deferved the 
 name of difeafe, as they were fo flight as to be fcarcely per¬ 
 ceptible, except that I could conned! a flight head-ache and 
 langour, with a fliffnefs and rather painful fenfation in the 
 axilla. This latter fymptom was the mod; Ariking, it re¬ 
 mained from twelve to forty-eight hours. In no cafe did I 
 obferve the fmallefl puflule, or even difcolouration of the ikin 
 like an incipient puflule, except about the part where the virus, 
 had been applied. 
 
 “ After all thefe fymptoms had fubflded, and the arms were 
 well, I inoculated four of this number with variolous matter, 
 taken from a patient in another regiment. In each of thefe it 
 was inferted feveral times under the cuticle, producing flight 
 inflammation on the fecond or third day, and always difappear- 
 ing before the fifth or fixth; except in one who had the Cow 
 Pox in Gloucefterfliire before he joined us, and who alfo 
 received it at this time by inoculation. In this man the pundture 
 
 3 inflamed 
 
[ i6 5 ] 
 
 inflamed, and his arm was much forer than from the infertion of 
 the Cow Pox virus ; but there was no pain in the axilla, nor 
 could any conftitutional affe&ion be obferved. 
 
 • . '' I: ' 
 
 “ I have only to add, that I am now fully fatisfied of the 
 efficacy of the Cow Pox in preventing the appearance of the 
 Small Pox, and that it is a mod; happy and falutary iubflitute 
 for it. 
 
 s ‘ I remain, &c. 
 
 “ M. Jb Tierny.” 
 
 Although the fufceptibility of the virus of the Cow Pox is 
 for the mod part lod: in thofe who have had the Small Pox, yet 
 in fome conftitutions it is only partially deftroyed, and in others 
 it does not appear to be in the lead; diminiftied. 
 
 By far the greater number, on whom trials were made, re¬ 
 dded it entirely ; yet I found fome on whofe arms the puftule 
 from inoculation was formed completely, but without producing 
 
 Z « the 
 
 v 
 
[ i66 ] 
 
 the common efflorefcent blufh around it, or any conflitutionai 
 illnefs, while others have had the difeafe in the molt perfect 
 manner. A cafe of the latter kind having been prefented to me 
 by Mr. Fewfter, Surgeon, of Thornbury, I fhall infert it. 
 
 “ Three children were inoculated with the vaccine matter you 
 obligingly lent me. On calling to look at their arms three days 
 after, I was told that John Hodges, one of the three, had been 
 inoculated with the Small Pox when a year old, and that he had 
 a full burthen, of which his face produced plentiful marks, 
 a circumfkmce I was not before made acquainted with. On the 
 lixth day the arm of this boy appeared as if inoculated with 
 variolous matter, but the pultule was rather more elevated. On 
 the ninth day he complained of violent pain in his head and 
 back, accompanied with vomiting and much fever. The next 
 day he was very well, and went to work as ufual. The punc¬ 
 tured part began to fpread, and there was the areola around the 
 inoculated part to a conliderable extent. 
 
 “ As this is contrary to an aflertion made in the Medical and 
 2 Phyfical 
 
[ i 6 7 J 
 
 Phyfical Journal, No, 8, I thought it right to give you this 
 information, and remain, 
 
 44 Dear Sir, &e, 
 
 “ ]. Fewster.” 
 
 \ 
 
 It appears then that the animal economy with regard to the 
 a&ion of this virus is under the fame laws as it is with refped 
 to the variolous virus, after previoufly feeling its influence, as 
 far as comparifons can be made between the two difeafes. 
 
 Some ffriking inftances of the power of the Cow Pox in 
 fufpending the progrefs of the Small Pox after the patients had 
 been feveral days cafually expofed to the infection have been 
 laid before me, by Mr. Lyford, Surgeon, of Winchefler, and 
 my nephew the Rev. G. C. Jenner. Mr. Lyford, after giving 
 an account of his extenlive and fuccefsful pra&ice in the vaccine 
 inoculation in Hampfhire, writes as follows : 
 
 f ■ ^ , V. 
 
 / 
 
 4 4 The following Cafe occurred to me a fhort time fince, and 
 
 Z 2 • may 
 
[ 168 ] 
 
 may probably be worth your notice. I was fent for to a patient 
 
 with the Small Pox, and on inquiry found that five days 
 
 previous to my feeing him the eruption began to appear. 
 
 % 
 
 During the whole of this time two children, who had not had 
 the Small Pox, were conftantly in the room with their father, 
 and frequently on the bed with him. The mother confulted 
 me on the propriety of inoculating them, but objected to my 
 taking the matter from their father, as he was fubjed to eryfi- 
 pelas. I advifed her by all means to have them inoculated at 
 that time, as I could not procure any variolous matter elfewhere. 
 However, they were inoculated with vaccine matter, but I 
 cannot fay I flattered myfelf with its proving fuccefsful, as they 
 had previoufly been fo long and ftill continued to be expofed to 
 the variolous infedion. Notwithfianding this I was agreeably 
 furprifed to find the vaccine difeafe advance and go through its 
 regular courfe; and, if I may be allowed the expreffion, to the 
 total extindion of the Small Pox.” 
 
 Mr. Jenner’s Cafes were not lefs fatisfadory. He writes as 
 follows : 
 
 A fon 
 
[ i69 3 
 
 “ A fon of Thomas Stinchcomb of Woodford, near Berkeley, 
 was infedted with the natural Small Pox at Bridol, and came 
 home to his father’s cottage. Four days after the eruptions had 
 appeared upon the boy, the family (none of which had ever had 
 the Small Pox) confiding of the father, mother, and five 
 children, was inoculated with vaccine virus. On the arm of 
 the mother it failed to produce the lead effedt, and fhe of courfe 
 
 t i, 
 
 had the Small Pox*, but the red of the family had the Cow 
 Pox in the ufual mild way, and were not affedted with the Small 
 Pox, although they were in the fame room, and the children 
 dept in the fame bed with their brother who was confined to it 
 with the natural Small Pox j and fubfequently with their mother. 
 
 I . y 
 
 “ I attended this family with my brother Mr. H. Jenner.” 
 
 The following Cafes are of too fingular a nature to remain 
 unnoticed. 
 
 * Under fimilar circutnftances I think it would be advifeable to infert the 
 matter into each arm, which would be more likely to infure the fuccels of the 
 operation. E_ J* 
 
 Mil's- 
 
[ 1 7 0 ] 
 
 Mifs R--, a young lady about five years old, was feizcd 
 
 on the evening of the eighth day after inoculation with vaccine 
 virus, with fuch fymptoms as commonly denote the acceffion 
 of violent fever. Her throat was alfo a little fore, and there 
 were fome uneafy fenfations^ about the mufcles of the neck. 
 The day following a rafh was perceptible on her face and neck, 
 fo much refembling the efflorefcence of the Scarlatina Angi - 
 
 nofa , that I was induced to afk whether Mifs R- had been 
 
 expofed to the contagion of that difeafe. An anfwer in the 
 affirmative, and the rapid fpreading of the rednefs over the 
 fkin, at once relieved me from much anxiety refpedling the 
 nature of the malady, which went through its courfe in the 
 ordinary way, but not without fymptoms which were alarming, 
 both to myfelf and Mr. Lyford, who attended with me. There 
 
 i 
 
 was no apparent deviation in the ordinary progrefs of the puftule 
 to a ftate of maturity, from what we fee in general; yet there 
 was a total fufpenfion of the Areola or florid difcolouration 
 around it, until the Scarlatina had retired from the con- 
 
 flitution. 
 
 t 
 
/ 
 
 [ m 1 
 
 ftitution. As foon as the patient was freed from this difeafe, 
 this appearance advanced in the ufual way*. 
 
 The Cafe of Mifs H-- R— is not lefs interefting than 
 
 that of her fitter above related. She was expofed to the con¬ 
 tagion of the Scarlatina at the fame time, and fickened almofl 
 at the fame hour. The fymptoms continued fevere about twelve 
 hours when the Scarlatine-rafh fhewed itfelf faintly upon her 
 face, and partly upon her neck. After remaining two or three 
 hours it fuddenly difappeared, and fhe became perfectly free 
 from every complaint. My furprife at this fudden tranfition 
 from extreme ficknefs to health, in great meafure ceafed when 
 I obferved that the inoculated puttule had occafioned, in this 
 cafe, the common efflorefcent appearance around it, and that 
 as it approached the centre it was nearly in an eryfipelatous 
 
 * I witneffed a fimilar fa£t in a cafe of Mealies*. The puftule from the Cow 
 Pock virus advanced to maturity, while the Meades exifted in the conftitution, 
 but no efflorefcence appeared around it until the Mealies had ceafed to exert its 
 influence. 
 
 * Sec page 55. 
 
 hate. 
 
 1 
 
[ * 7 2 3 
 
 Hate. But the moil remarkable part of this hiflory is, that on 
 the fourth day afterwards, as foon as the efflorefcence began to 
 die away upon the arm, and the puftule to dry up, the Scar¬ 
 latina again appeared, her throat became fore, the rafh fpread 
 all over her. She went fairly through the difeafe, with its 
 common fymptoms. 
 
 * 
 
 That thefe were actually Cafes of Scarlatina , was rendered 
 certain by two fervants in the family falling ill at the fame time 
 with the diftemper, who had been expofed to the infedlion with 
 the young ladies. 
 
 Some there are who fuppofe the fecurity from the Small Pox 
 obtained through the Cow Pox will be of a temporary nature 
 only. This fuppolition is refuted not only by analogy with 
 refped: to the habits of difeafes of a fimilar nature, but by in¬ 
 controvertible fadls, which appear in great numbers againft it. 
 To thofe already adduced in the former part of my firft Treatife* 
 
 * Seepages 9, 11, 12, 13, 14, 20, &c. 
 
 many 
 
[ 173 3 
 
 many more might be added were it deemed neceflary; but 
 among the Cafes I refer to, one will be found of a perfon who 
 had the Cow Pox fifty-three years before the effect of the Small 
 Pox was tried upon him. As he completely refilled it, the 
 intervening period I conceive mull neceflarily fatisfy any reafon- 
 able mind. Should further evidence be thought neceflary, I 
 ihall obferve that among the Cafes prefen ted to me by Mr. Fry, 
 Mr. Darke, Mr. Tierny, Mr. H. Jenner, and others, there were 
 many whom they inoculated ineffectually with variolous matter, 
 who had gone through the Cow Pox many years before this trial 
 was made. 
 
 It has been imagined that the Cow Pox is capable of being 
 communicated from one perfon to another by effluvia without 
 the intervention of inoculation. My experiments, made with 
 the defign of afcertaining this important point, all tend to 
 eflablifli my original pofition, that it is not infectious, except by 
 contaCl. I have never hefitated to fuffer thofe on whofe arms 
 there were puflules exhaling the effluvia, from aflociating or even 
 fleeping with others who never had experienced either the Cow 
 
 A a Pox 
 
> 
 
 [ 174 J 
 
 Pox or the Small Pox. And further, l have repeatedly among 
 children caufed the uninfedted to breathe over the inoculated 
 vaccine puftules during their whole progrefs, yet thefe experi¬ 
 ments were tried without the lead: effedt. However, to fubmit 
 a matter fo important to a dill further fcrutiny, I defired Mr. 
 H. Jenner to make any further experiments which might 
 flrike him as mod: likely to edablifli or refute what had been 
 advanced on this fubjedt. He has fince informed me, “ that he 
 inoculated children at the bread:, whofe mothers had not gone 
 through either the Small Pox or the Cow Pox; that he had 
 inoculated mothers whofe fucking infants had never undergone 
 either of thefe difeafes; that the effluvia from the inoculated 
 puifules, in either cafe, had been inhaled from day to day during 
 the whole progrefs of their maturation, and that there was not 
 the lead: perceptible effect from thefe expofures. One woman 
 he inoculated about a week previous to her Accouchment , that 
 her infant might be the more fully and conveniently expofed to 
 the pudule; but, as in the former indances, no infedtion was 
 given, although the child frequently dept on the arm of its 
 mother with its nodrils and mouth, expofed to the pudule in the 
 
 fulled; 
 
[ 175 1 
 
 fulled date of maturity. In a word, is it not impoffible for the 
 Cow Pox, whofe only manifedation appears to confid in the 
 pudules created by contact, to produce itfelf by effluvia ? 
 
 In the courfe of a late inoculation, I obfcrved an appearance 
 which it may be proper here to relate. The pundtured part 
 on a boy’s arm (who was inoculated with frefli limpid virus) 
 on the dxth day, indead of fhewing a beginning veficle, 
 which is ufual in the Cow Pox at that period, was en- 
 cruded over with a rugged amber-coloured fcab. The fcab 
 continued to fpread and increafe in thicknefs for fome days, 
 when at its edges a veficated ring appeared, and the difeafe went 
 through its ordinary courfe, the boy having had forenefs in the 
 axilla, and fome fight indifpodtion. With the fluid matter 
 taken from his arm, five perfons were inoculated. In one it 
 took no effedt. In another it produced a perfect pufiule without 
 any deviation from the common appearance; but in the other 
 three the progrefs of the inflammation was exadtly fimilar to the 
 indance which afforded the virus for their inoculation; there 
 was a creeping fcab of a loofe texture, and fubfequently the 
 
 A a 2 formation 
 
✓ 
 
 [ ] 
 
 formation of limpid fluid at its edges. As thefe people were all em¬ 
 ployed in laborious exercifes, it is poffible that thefe anomalous 
 appearances might owe their origin to the fridion of the clothes 
 on the newly-inflamed part of the arm. I have not yet had an 
 opportunity of expofing them to the Small Pox. 
 
 In the early part of this Inquiry I felt far more anxious re- 
 fpeding the inflammation of the inoculated arm than at prefent; 
 yet that this afledion will go on to a greater extent than could 
 be wifhed is a circumftance fometimes to be expeded. As this 
 can be checked, or even entirely fubdued by very Ample means, 
 I fee no reafon why the patient fhould feel an uneafy hour 
 becaufe an application may not be abfolutely neceflary. About 
 the tenth or eleventh day, if the puflule has proceeded regularly, 
 the appearance of the arm will almoft to a certainty indicate 
 whether this is to be expeded or not. Should it happen, 
 nothing more need be done than to apply a Angle drop of the 
 Aqua Lythargyr. Acctati* upon the puflule, and having fuller¬ 
 ed it to remain two or three minutes, to cover the efflorefcence 
 
 * Extract of Saturn., 
 
 furrounding 
 
[ *77 ] 
 
 furrounding the puflule with a piece of linen dipped in the 
 Aqua Lythargyr . Compos .* The former may be repeated 
 twice or thrice during the day, the latter as often as it may feel 
 agreeableto the patient. 
 
 When the fcab is prematurely rubbed off, (a circumflance 
 not unfrequent among children and working people) the ap¬ 
 plication of a little Aqua Lythargyri Acct. to the part, immedi¬ 
 ately coagulates the furface, which fupplies its place, and 
 prevents a fore.. 
 
 In my former Treatifes on this fubjed I have remarked that 
 the human conftitution frequently retains its fufceptibility of the 
 Small Pox contagion (both from effluvia and contad) after 
 previoufly feeling its influence. In further corroboration of 
 this declaration, many fads have been communicated to me by 
 various correfpondents. I fhall feled one of them. 
 
 * Goulard Water. For further information on this fubjedl fee the lirft 
 Treatife on the Var. Vac. Dr, Marlhall’s Letters, &c. 
 
 Dear 
 
 i 
 
[ i/8 ] 
 
 “ Dear Sir, 
 
 “ Society at large muft I think feel much indebted to you 
 for your Inquiries and Obfervations on the Nature and Effedts 
 of the Variolae Vaccinse, &c. See. As I conceive what I am 
 now about to communicate to be of fome importance, I imagine 
 it cannot be uninterefting to you, efpecially as it will ferve to 
 corroborate your ahertion of the fufeeptibility of the human 
 fyflem of the variolous contagion, although it has previoufly 
 been made fenfible of its adtion. In November 1793, I was 
 deiired to inoculate a perfon with the Small Pox. I took the 
 variolous matter from a child under the difeafe in the natural 
 way, who had a large burthen of diftindt puftules. The mother 
 of the child being defirous of feeing my method of communi¬ 
 cating the difeafe by inoculation, after having opened a puftule, 
 I introduced the point of my lancet in the ufual way on the 
 back part of my own hand, and thought no more of it until I 
 felt a fenfation in the part, which reminded me of the tranfac- 
 tion. This happened upon the third day; on the fourth there 
 were all the appearances common to inoculation, at which I was 
 
 2 not 
 
 t 
 
[ l 79 1 
 
 not at all furprifed, nor did I feel myfelf uneafy upon per¬ 
 ceiving the inflammation continue to increafe to the fixth and 
 feventh day, accompanied with a very fmall quantity of fluid, 
 repeated experiments having taught me it might happen fo with 
 perfons who had undergone the difeafe, and yet would efcape 
 any conAitutional affection : but I was not fo fortunate; for on 
 the eighth day I was feized with all the fymptoms of the eruptive 
 fever, but in a much more violent degree than when I was before 
 inoculated, which was about eighteen years previous to this, when 
 I had a confiderable number of pu Aides. I mu A confefs I was 
 now greatly alarmed, although I had been much engaged in the 
 Small Pox, having at different times inoculated not lefs than 
 two thoufand perfons. I was convinced my prefent indifpoA- 
 tion proceeded from the infertion of the variolous matter, and 
 therefore anxioufly looked for an eruption. On the tenth day I 
 felt a very unpleafant fenfation of Aiffnefs, and heat on each 
 Ade of my face near my ear, and the fever began to decline. 
 
 The affection in my face foon terminated in three or four 
 
 puAules- 
 
[ i8o ] 
 
 puflulcs attended with inflammation, but which did not ma¬ 
 turate, and I was prefently well. 
 
 i 
 
 I remain, Dear Sir, &c. 
 
 “ Thomas Miles.” 
 
 This Inquiry is not now fo much in its infancy as to reflrain 
 me from fpeaking more pofitively than formerly on the im¬ 
 portant point of Scrophula as connected with the Small Pox. 
 
 Every practitioner in medicine, who has extenfively inocu¬ 
 lated with the Small Pox, or has attended many of thofe who 
 have had the diftemper in the natural way, muft acknowledge 
 that he has frequently feen fcrophulous affedtions, in fome form 
 or another, fometimes rather quickly {hewing themfelves after 
 the recovery of the patients. Conceiving this fad to be ad¬ 
 mitted, as I prefume it muft be by all who have carefully attend¬ 
 ed to the fubjeCt, may I not afk whether it does not appear 
 
 probable 
 
[ 181 ] 
 
 probable that the general introduction of the Small Pox into 
 Europe has not been among the moil conducive means in ex¬ 
 citing that formidable foe to health ? Having attentively watched 
 the effeCts of the Cow Pox in this refpeCt, I am happy in being 
 able to declare, that the difeafe does not appear to have the lea l 
 tendency to produce this deftruCtive malady. 
 
 * 
 
 The fcepticifm that appeared even among the moff enlightened 
 of medical men when my fentiments on the important fubjeCf of 
 the Cow Pox were firff promulgated, was highly laudable. 
 To have admitted the truth of a doCtrine, at once fo novel and 
 fo unlike any thing that ever had appeared in the Annals of 
 Medicine, without the teff of the moff rigid fcrutiny, would 
 have bordered upon temerity; but now, when that fcrutiny has 
 taken place, not only among ourfelves but in the firff profeffional 
 circles in Europe, and when it has been uniformly found in fucn 
 abundant inffances that the human frame, when once it has felt 
 the influence of the genuine Cow Pox in the way that has been 
 defcribed, is never afterwards at any period of its exiffence 
 a flail able by the Small Pox, may I not with perfeCf confidence 
 
 B b congratulate 
 
. [ . *»a ] 
 
 congratulate my country and fociety at large on their beholding, 
 in tire mild form of the Cow Pox, an antidote that is capable of 
 .extirpating from the earth a difeafe which is every hour de¬ 
 vouring its victims; a difeafe that has ever been considered as 
 the fevered; Scourge of the human race 1 
 
 FINIS* 
 
 PRINTED BY SAMPSON LOW, BERWICK STREET, SOHO, 
 
ERRATAt 
 
 Line 
 
 3, after fmgular dele comma * 
 
 13, infert to be after is not. 
 
 8, for and read an. 
 
 5, for csnverfation read obfervation 
 

 
 
 
 
 
 
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