LIBRARY OF CONGRESS. I 
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 c&dtr/i S.C/.u>oib I 
 
 UNITED STATES OF AMERICA.! 
 
/ 
 
 Contagious* Epidemic Diseases 
 
 CONSIDERED WITH REFERENCE TO 
 
 Quarantine and Sanitary Laws. 
 
 IS YELLOW FEVER CONTAGIOUS ? 
 
 BY- 
 
 C. W. CHANCELLOR, M. D. 
 
 Late Professor of Surgery in the Washington University, Baltimore 
 Secretary of the State Board of Health of Md.; Member of 
 the American Public Health Association ; Editor of 
 the "Sanitary Messenger," &*c, &*c, &*c. 
 
 .BALTIMORE: 
 
 PBI1TTED B"2T TOH1T COX, 
 Corner Pratt Street & Spear's Wharf. 
 
 1878. 
 

 PROPOSITIONS 
 
 i. WHAT IS A CONTAGIOUS DISEASE? 
 
 2. WHAT IS AN EPIDEMIC DISEASE? 
 
 3. IS YELLOW FEVER CONTAGIOUS? 
 
THE 
 
 CONTAGIOUSNESS OF YELLOW FEVER. 
 
 In collecting, enforcing and adding to the evidence accu- 
 mulated upon this most important subject, no claim is laid 
 to originality ; the facts p resented are simply a reproduc- 
 tion of the experience and opinions of wise investigators, 
 given for the most part in their own language. Its value 
 does not consist in vague speculations, based upon limited 
 experience, hut in the mass of evidence gathered from the 
 researches and writings of experienced and reliable scientists. 
 
 A contagious disease is a disease which is communicated 
 from person to person. An epidemic disease is a disease 
 which at certain periods prevails over the whole, or over 
 a large portion of a community. A sporadic disease is 
 a disease which arises either in a single instance, or of 
 which the cases at one time are few and scattered. The 
 cause of a contagious disease is a specific animal poison. 
 The cause of an epidemic disease is, or rather is supposed to 
 he, a certain condition of the air. A contagious disease pre- 
 vails hy the communication from person to person of that 
 specific animal poison from which the malady derives its 
 existence. An epidemic disease prevails through the in- 
 fluence of the atmosphere. The specific animal poison which 
 gives origin to a contagious disease must have existed in 
 some person, and have heen communicated from that person 
 to another, by actual contact, before such a disease can be 
 propagated. The application by contact of its own specific 
 virus is indispensable, as a first step, to the progress of a 
 
contagious disease ; it is essential to every subsequent step. 
 For the extension of an epidemic disease, on the contrary, it 
 is only necessary that a person (provided he be predisposed 
 to receive the malady,) be surrounded by the noxious air 
 from which the epidemic arises. A distinction has, indeed, 
 been made between contagious disease which is communi- 
 cable by palpable matter, and one which is communicable 
 by invisible effluvia. Whether its application to any part 
 of the body of the individual who receives it, can be dis- 
 tinctly traced or not, it must come in contact with some part 
 of his body. The small-pox is communicable by the appli- 
 cation to a healthy person of the matter contained in its pus- 
 tules, it is also communicable by placing a healthy person 
 within a certain distance of the diseased ; in the former case 
 the application of the morbid matter is palpable ; in the lat- 
 ter case it is not palpable, it is too subtle to be appreciated 
 by the senses, it is conveyed through the medium of the air; 
 but its application is as real, and as really by contact, as 
 when it is applied by the lancet of the innoculator. fc 
 
 In the whole range of politics, nay, even in that of theo- 
 logy itself, there is no subject on which such vague notions 
 have prevailed ; none respecting which men's minds have 
 been so completely and so generally mystified as that of con- 
 tagion. The subject of contagion certainly opposes to its 
 investigation no particular difficulties ; but by the aid of one 
 enormous assumption, and by neglecting to distinguish be- 
 tween one or two circumstances, which it is essential to dis- 
 criminate, the extent to which both medical and unprofes- 
 sional men of the grea f est intelligence have allowed their 
 understanding to be abused, is perfectly astonishing. For 
 several centuries the subject of contagion has had the singu- 
 lar property of depriving the physician, the philosopher and 
 the statesman of the power of applying to its investigation 
 the commonest rules of reasoning ; and men have argued on 
 this topic, apparently to their own satisfaction, and to that 
 of others, in a manner which would have covered them with 
 shame, and overwhelmed them with contempt, had they so 
 done with reference to any other subject of human inquiry. 
 
And yet it is a subject on which it is of great importance that 
 the ideas should be clear and the judgment sound. It is in- 
 timately connected with the life or death of millions of the 
 human race ; it is interwoven with the commercial welfare 
 of nations, and with the interests of this country in particu- 
 lar ; and the whole system of quarantine laws should be en- 
 tirely dependent upon it. To this subject the anxious attention 
 of national legislatures has been directed more than once. In 
 1824 a committee of the House of Commons thus recorded 
 their opinion on the matter: "The influence which this 
 law (that of quarantine) is supposed to have in the protection 
 of public health, its bearing on some of our strongest preju- 
 dices, and its containing the various precautions which have 
 been long deemed our safeguards against the introduction of 
 contagious diseases, from whatever part of the world the 
 danger may be apprehended, renders every recommendation 
 that may affect it a matter at once of general interest and 
 peculiar delicacy. On the one hand care is to be taken that 
 in the attempt to relieve commerce from burthens and in- 
 conveniences which press upon it, and to afford it the greatest 
 freedom of which it is susceptible, we do not expose the 
 country to the most formidable risk. On the other hand, 
 that neither ancient prejudices, nor an excess of anxiety to 
 avert possible danger, should induce the continuance of re- 
 strictions inessential to their object ; and should thus deny 
 to the trade any of those facilities which, consistently with 
 every prudential regard to considerations of protection and 
 safety, it may be permitted to enjoy." 
 
 The subject is now about to undergo an investigation by a 
 Committee of the Senate and House of Representatives of 
 the United States, and it is of the utmost importance that 
 those who are to engage in the inquiry should come to it 
 with some real and correct information, and with unpreju- 
 diced minds. The data submitted to the American Public 
 Health Association, at its late meeting in Richmond, Va., 
 was not sufficient to justify that body in committing itself to 
 any special theory in connection with the origin and preven- 
 tion of yellow fever, notwithstanding the manifest prejudice 
 
6 
 
 with which many came to the meeting in favor of declaring 
 yellow fever a contagious disease. In this instance igno- 
 rance was not blamable, and prejudice was unavoidable, for 
 the investigation was hastily instituted, and the report of the 
 commission was neither complete nor exhaustive. 
 
 CONTAGIOUS DISEASES. 
 
 Before proceeding to consider the question of contagion, it 
 may be proper to observe that it is by no means exclusively 
 a medical question ; it is really a question of science, to be 
 decided by facts which every one can understand ; a question 
 of testimony, to be determined by evidence which every one 
 can appreciate. There are circumstances which render medi- 
 cal men peculiarly unfit to investigate the subject. Few 
 members of a profession are capable of taking anything but 
 a professional view of any professional subject. In medicine 
 the authority of the master has at least as much influence 
 over the mind of the student as it has in any other science. 
 On this subject, in particular, pupils, before they are capable 
 of forming an opinion for themselves, are taught in the 
 schools certain dogmas, which are inculcated upon them 
 with extraordinary earnestness ; their minds a»e trained to 
 take only one view of a subject, and to consider all doubt on 
 the matter as leading to tbe most terrible consequences. It 
 is, therefore, only now and then that a man arises, endowed 
 with extraordinary power, or placed in circumstances pecu- 
 liarly favorable to the discovery of the truth, who is found 
 capable of making that mental effort, which it is necessary 
 to exert in order to unlearn ; to disregard the undue author- 
 ity of the master ; to look into nature as an original and in- 
 dependent observer ; to see what is passing around him with 
 his own eyes, and to judge with his own understanding. 
 Among the members of the Spanish Cortes, in 1822, there 
 were nine medical men. The subject of contagion was 
 brought before the consideration of that body. It was a 
 subject in which the Spanish Cortes could not but feel a deep 
 interest, in consequence of the fever which had so recently 
 
depopulated numerous cities of the Peninsula. So over- 
 whelming did the evidence adduced to prove that the fever 
 which had lately raged in Spain was not contagious, appear 
 to the Assembly, that, in opposition to the unanimous opin- 
 ion of the nine medical men of their own body, as well as 
 that of an immense majority of the physicians of Spain, they 
 rejeeted altogether, after a solemn debate, and by a majority 
 of sixty-rive to forty-eight votes, the project of a code of san- 
 itary laws, which had been for years in careful preparation, 
 successively by a commission of the government, and two 
 committees of the Public Health of the Cortes. Here evi- 
 dence in support of an undoubted truth, relating to a ques- 
 tion which might have been deemed exclusively professional, 
 sufficient to satisfy a majority of sixty-rive to forty-eight un- 
 professional members, was not sufficient to satisfy a single 
 individual out of nine professional men ! 
 
 It has been stated that a contagious disease is a disease 
 capable of being communicated from person to person. It is 
 produced by an animal poison, and it has no other known 
 cause. This animal poison is the product of a peculiar secre- 
 tion of the animal economy. The character which is essen- 
 tial to it is the power of producing, when applied to a healthy 
 person, a similar disease. 
 
 All the diseases to which the human body is subject are 
 divided into acute and chronic. Contagious diseases, in like 
 manner, are either of an acute or chronic character. Exam- 
 ples of acute contagious disc sea are the small-pox and 
 measles: of the chronic the venereal, the itch, and a few 
 othe - 
 
 That species of contagion by which certain chronic dis- 
 eases are propagated is so obvious as to require no discussion. 
 The morbid secretion upon which it depends is palpable, the 
 application of it is direct, the effects are visible, and can be 
 observed and marked through every stage, from their com- 
 mencement to their termination. With the single exception 
 already adverted to, the same is true of that species of con- 
 tagion upon which acute diseases depend. The small-pox 
 secretes a contagious matter which is contained in its pus- 
 
8 
 
 tules ; the measles secretes a contagious matter which is con- 
 tained in its vesicles. Apply a portion of the fluid con- 
 tained in the pustules of the one, and the Vesicles of the 
 other, to a healthy person ; it will excite the same train 
 of symptoms as existed in the individual in whom the con- 
 tagious matter was secreted. Moreover, persons who ap- 
 proach within a short distance of the affected, and who do not 
 come into actual contact with them, are often attacked by 
 these maladies ; but this is never the case with chronic con- 
 tagious diseases, in all of which the contact must be direct. 
 It has been already shown, however, that even in the former 
 the contact is no less real, though it is not visible, and that 
 the contagious matter, in a form too subtle to be appreciated 
 by the senses, is conveyed from one body to another. The 
 origin of contagious matter, like the origin of every natural 
 production, is concealed from the scrutiny of man. We 
 know nothing of it ; but of the nature of the diseases.it pro- 
 duces, this much, at least, is certain, that they depend upon 
 a peculiar animal poison, and that they are propagated by 
 the communication of that poison from person to person. 
 
 It would have been reasonable to suppose a priori that 
 diseases arising from causes thus specific, would observe 
 peculiar laws. They are found to do so, and a knowledge 
 of these laws is essential to the understanding of this subject. 
 
 1. Contagious diseases produce certain phenomena ; that 
 is, a combination of certain symptoms. These symptoms are 
 determinate and uniform ; they are always the same ; they 
 never vary, except in degree. In every individual, under 
 every variety of age, sex, condition and mode of living, in 
 every country, in every season of the year, % and in all possi- 
 ble states of the atmosphere, these symptoms are precisely 
 the same. The operation of any one, or of any combination 
 of these agents, so powerful in modifying disease in general, 
 is only to render the symptoms of a contagious disease more 
 or less mild or malignant. The symptoms themselves are 
 uniformly the same. The small. pox is never without its 
 pustules ; the measles is never without its vesicles ; the 
 virus of small-pox never produces the symptoms of measles ; 
 
that of measles never produces the symptoms of small-pox. 
 Each disease preserves, under every variety of circumstance, 
 the same specific character. 
 
 2. The phenomena produced by contagious diseases are 
 not only determinate in themselves, but they are uniform in 
 their accession, in their progress, and in their termination. 
 Beyond certain limits, which are narrow and fixed, they 
 never vary in either of these respects. The small-pox pro- 
 duces its appropriate symptoms in a certain time after the 
 contagious matter has been received. First, certain symp- 
 toms arise ; these are succeeded by others ; this succession 
 takes place in a certain order ; the symptoms come to their 
 height in a certain period ; they decline in a certain man- 
 ner ; they terminate in a certain time. The period also 
 when the disease has run its course, and ceases to be con- 
 tagious, that is, ceases to exist, is determinate. All these 
 things are regular as the course of the planets. In small- 
 pox the law of the disease is that no contagion takes place 
 until the eruption appears ; and that it remains as long as 
 there is any scab on the skin. The period whicli elapses 
 between the reception of the contagious matter and the first 
 appearance of the disease in small-pox from innoculation is 
 8 or 9 days. Thus, of 810 inoculated cases, in 519 fever 
 commenced before the ninth, in 219 on the ninth day. The 
 exceptions are extremely rare in which it either anticipates 
 or exceeds this period. In the casual, or what is called the 
 natural small-pox, the latent period is somewhat longer than 
 in the innoculated ; but the utmost range is only from ten to 
 sixteen days. The latent period of the contagion of measles 
 is from ten to fourteen days. The other phenomena of these 
 diseases succeed each other with a like regularity. 
 
 3. The morbid matter producing a contagious disease 
 being once secreted, that disease can be propagated at any 
 time, and among any number of persons. So long as it re- 
 tains its energy this specific virus never ceases to produce its 
 specific effects ; these effects can be produced by no other 
 cause. From this law it follows that no disease which is not 
 contagious at its commencement can become contagious in 
 
10 
 
 its progress. The spontaneous generation of a contagious 
 disease is as great an absurdity as the spontaneous genera- 
 tion of an animal. Nor, on the other hand, can a. disease 
 which is contagious in its commencement cease to be conta- 
 gious in its progress. The notion that a fever may arise 
 from cold, from wet, from a peculiar constitution of the 
 atmosphere, or from any of the common causes of fever, and 
 become contagious in its progress, originated in an ignorance 
 of the laws of the animal economy, and has been perpetuated 
 in consequence of inattention to those laws. No man of 
 sense can consider what a contagious disease really is, and 
 what the ascertained laws of the animal economy are, with- 
 out perceiving that this notion of the generation of a con- 
 tagion must be false. To suppose, indeed, that a disease 
 non-contagious in its commencement may become contagious 
 in its progress, or the converse, is to imagine in the animal 
 economy precisely the same absurdity as it would be in the 
 vegetable were an acorn, by a change of soil or climate, to 
 cease to produce an oak and generate a bramble. 
 
 4. Acute contagious diseases, as a general rule, are capa- 
 ble of affecting the same person once only ; chronic conta- 
 gious diseases are capable of affecting the same person more 
 than once. On what this peculiarity depends we do not 
 know ; it is an ultimate fact, but the fact itself is certain. 
 Cases, indeed, are on record of the occurrance of acute con- 
 tagions, as small-pox and measles, more than once in the 
 same individual ; allowing the perfect accuracy of the ob- 
 servations on which these statements are made, it must still 
 be conceded that it is an event so seldom witnessed that it 
 can be ranked only with the most singular of the exceptions 
 which are known to exist to any general rule. 
 
 5. Strictly connected with this law, and as a consequence 
 of it, there follows one negative character of an acute conta- 
 gious disease, namely — when it has once gone through its 
 course there can be no relapse. It is impossible, either in 
 that weakened state of the body which immediately succeeds 
 an acute disease, or in any other condition of the constitu- 
 tion, whether by exposure to the common causes of fever, or 
 
11 
 
 by an application of the specific virus in any degree of inten- 
 sity, to re-excite the original train of symptoms. 
 
 It might reasonably have been thought impossible that 
 diseases so uniform, so specific, could be confounded with 
 any other maladies. Yet there is an important class of dis- 
 eases with which they have been generally confounded, and 
 with which they not only have nothing in common, but to 
 which they afford a perfect contrast, namely — 
 
 EPIDEMIC DISEASES. 
 
 The term epidemic, considered etymologically, merely sig- 
 nifies generally prevailing; but in medicine it is universally 
 appropriated to designate a certain class of fevers. These 
 fevers are highly malignant ; they occur frequently ; they 
 spread extensively ; they prove more mortal than all other 
 diseases together. Supposing mankind to consist of one 
 thousand millions ; it is computed that thirty millions die 
 annually from all diseases, and that of this number fifteen 
 millions, that is one-half, die of epidemic maladies. These 
 diseases, therefore, possess an extraordinary interest and im- 
 portance. Epidemic diseases appear to derive their origin 
 from one cause, namely — the state of the air. A certain 
 condition of the air is supposed to produce epidemic diseases, 
 because the hypothesis affords the best solution of all the 
 phenomena which they exhibit. What that constitution of 
 the atmosphere is which gives rise, in any case, to an epi- 
 demic disease, we do not know ; therefore we cannot know 
 what the peculiar constitution of the atmosphere is which 
 gives rise to peculiar epidemics. This is the all-important 
 question. It is reasonable to believe that there are certain 
 qualities of the atmosphere which have a considerable in- 
 fluence in the generation of these diseases, namely — its heat, 
 cold, moisture, dryness, and electrical state ; but what de- 
 grees and combinations of these qualities are connected with 
 the production of epidemic diseases, we do not know. We 
 have derived from experience the certain knowledge of one 
 fact only, namely — that these maladies are generated most 
 
12 
 
 frequently, and in the most malignant form, by a moist and 
 warm atmosphere It has, morever, been supposed that cer- 
 tain changes may take place in the constitution of the air 
 which are not perceptible by our senses, and that these 
 changes may have the most important influence on human 
 health and life. These occult properties remain to be inves- 
 tigated. 
 
 In assigning certain conditions of the air as the cause of 
 epidemic diseases, we are able to advance one step. The air, 
 it is certain, is often charged with noxious exhalations aris- 
 ing from the putrefaction of animal and vegetable matter. 
 These exhalations are generated in certain localities, notably 
 where stagnant water contains dead vegetable matter ; and 
 their production is generally promoted by heat. Their pre- 
 cise nature is not known, for they have never been obtained 
 in a separate state ; but it is certain they are suspended in 
 the air ; that, naturally, they do not extend far beyond the 
 place where they are generated ; that by currents of wind 
 they are capable of being conveyed to a great distance ; that 
 they exert a powerful agency in producing some of the most 
 malignant fevers ; and that a long continued exposure to 
 them tends to shorten the duration of human life. 
 
 Epidemic diseases observe certain laws, and these laws, it 
 will be seen, are the complete contrast of those which regu- 
 late contagious diseases. 
 
 1. The phenomena of epidemic diseases are not determi- 
 nate and uniform ; they are diversified in the highest de- 
 gree ; not only in different countries and different seasons, 
 but in the same country and in the same season. These 
 symptoms observe no regular concourse ; they do not suc- 
 ceed each other in any determinate order ; there is no dis- 
 cernible connection between the application of their cause 
 and the appearance of its effects ; their duration is variable. 
 The phenomena of contagious diseases, on the contrary, as 
 has been shown, is determinate ; the order of their succession 
 is regular ; the period which elapses between the applica- 
 tion of their cause and the appearance of its effects is fixed ; 
 their duration is uniform. 
 
13 
 
 2. Though there is the greatest possible diversity in the 
 phenomena of epidemic diseases, yet in all countries the 
 periods at which they commence, decline and cease are some- 
 what determinate and exact. These periods correspond with 
 certain states of the season. They differ in different coun- 
 tries according to their geographical posi'ion, and they may 
 be anticipated or postponed by circumstances, but in general 
 they are remarkably uniform. In Asia Minor, Egypt and 
 Syria they commence in March or April, and cease in June 
 or July ; in most parts of Europe and in North America 
 they begin in July or August, and end in November or De- 
 cember. All ihe epidemics of yellow fever in the United 
 States, of which we have any certain record, have appeared 
 in June, July or August, and committed their greatest rav- 
 ages in the months of August, September and October. 
 
 3. Epidemic diseases commence, spread and cease in a 
 manner perfectly peculiar. They arise, for example, in 
 some particular quarter of a town, or in some district. They 
 do not proceed to attack other places in succession, accord- 
 ing to their proximity to the quarter first affected, but they 
 break out at once in the most distant and the most opposite 
 directions. They prevail, suppose, in a certain district; 
 suddenly they diminish or cease there, and appear in another 
 quarter, it may be, the most remote from the first ; then 
 they may again return to the place first attacked, or they 
 may suddenly appear in a spot near to it, or in one in an 
 opposite direction. People are attacked, not in proportion 
 as the inhabitants of the affected mix with those of the un- 
 affected places, but in proportion as the inhabitants of the 
 unaffected expose themselves to the air of theaffec ed places. 
 The visits of the sick to unaffected places is followed by no 
 increase of the disease, unless a favorable condition of the 
 atmosphere exists in the place ; the visits of the inhabitants 
 of an unaffected to an affected place is attended with a cer- 
 tain increase of sickness. The liability of persons to the 
 epidemic of yellow fever on their arrival in the infected dis- 
 trict is proverbial. On their removal from a noxious to a 
 pure air the sick often rapidly recover ; but they do not com- 
 
14 
 
 municate the disease to the inhabitants of a 'pure atmosphere. 
 The manner in which epidemic diseases terminate is most 
 peculiar and characteristic. It is precisely at the period 
 when the greatest number of persons are affected, and when 
 the greatest mortality prevails that these maladies rapidly 
 decline and suddenly cease. Ther.; is scarcely an exception 
 to this law in the history of epidemic diseases. It perfectly 
 accords with the nature of the cause upon which epidemics 
 are here supposed to depend ; it is totally inexplicable upon 
 the hypothesis that they are produced by contagion. To 
 suppose that a disease which is propagated by contagion can 
 rapidly decline, and even suddenly cease, at the very period 
 when the greatest number of persons are affected, and when 
 the greatest mortality prevails, that is, when the contagious 
 matter is proved to be in its most active and malignant state, 
 is utterly absurd. So true is this, that the most intelligent 
 and candid contagionists acknowledge, in so many terms, 
 that this important fact is perfectly inexplicable upon their 
 system. "It is a very common fact,'' says one of the most 
 distinguished and able advocates of the common doctrine of 
 contagion, ' c and perhaps wholly unaccountable upon any 
 theory of the propagation of contagion, that pestilential dis- 
 eases, after running an indefinite course, notwithstanding 
 all the measures adopted to restrain their progress, fre- 
 quently cease spontaneously, at a time when the walls of the 
 houses, furniture, &c, must still be supposed to be highly 
 impregnated with the contagion." The fact is indeed cer- 
 tain ; it is most distinctive of these two classes of diseases ; 
 it is alone sufficient to prove that they are essentially dif- 
 ferent. 
 
 Were the common term epidemic confined to its strict 
 etymological signification — generally prevailing — it would be 
 correct to say of the small pox, lor example, when gener- 
 erally prevailing, that it was epidemic. But this term 
 should be appropriated only to the designation of a class of 
 diseases observant of the laws which have been stated. To 
 call any disease epidemic, therefore, merely because it is gen- 
 erally prevailing, unless it be also obedient to all the other 
 
15 
 
 laws which characterize epidemic diseases, must lead (and 
 the history of this subject affords abundant proof that it has 
 led) to the most pernicious confusion of ideas. 
 
 It has been shown that fever is capable of being produced 
 by two causes : by a specific contagion, and by a peculiar 
 constitution of the air, which for the sake of distinguishing 
 it from its other states, and of expressing the fact that it is 
 the cause of epidemic diseases, may be termed its epidemic 
 constitution ; it is commonly called a pestilential constitu- 
 tion ; but fever is capable of beiug produced by another, and 
 a totally different condition of the air, namely, by the cor- 
 ruption of it. This corruption may take place in various 
 ways, and exist in various degrees of intensity, and its effects 
 will vary accordingly from the headache produced by a 
 crowded theatre to the mortal fever occasioned by such a 
 corruption of it as occurred in the black hole of Calcutta. 
 There is evident difference between an epidemic constitution 
 of the air, and a corruption of it. We know nothing what- 
 ever of the change of properties of the air which renders it 
 capable of producing pestilential fever ; investigation should 
 be specially directed to this point. The effects of an epi- 
 demic constitution of the air extend over a whole country, 
 or over a large portion of it, while the effects of a simple 
 corruption of the air are confined to that particular spot in 
 which the deterioration takes place. 
 
 Corruption of the air may be produced by three causes : 
 1st By the confinement of the healthy exhalations of the 
 body, as in crowded and ill-ventilated apartments. 2d. By 
 the confinement of the morbid exhalations of the human 
 body, as in hospitals where people laboring under diseases 
 are crowded together, and the air is filled with the poisonous 
 effluvia of sores, mortifications, dysenteric and other foeted 
 excrements. 3d. By exhalations arising from the putrefac- 
 tion of animal and vegetable matter. 
 
 Forestus mentions a malignant fever which raged at 
 Egmont in North Holland, occasioned by the putrefaction of 
 a whale which had been left on the shore. Senac gives an 
 account of a malignant fever which was excited by the ac- 
 
16 
 
 cumulation of the offal of a city without the walls. It was 
 received into a ditch filled with water ; while covered by the 
 water no bad consequences resulted ; but when the quantity 
 increased so that it rose above the surface, a dreadful fever 
 spread through the city and its neighborhood, so that where 
 four hundred used to die yearly, the deaths were increased to 
 two thousand. The malignant fevers which prevail in low 
 marshy situations, particularly in warm weather, are ex- 
 amples of the effect of the putrefaction of vegetable matter 
 in producing these diseases. Decaying vegetable matter 
 produces congestive malaria, and decaying animal matter 
 produces the type of miasma which causes typhoid or typhus 
 fever ; the atmosphere vitiated by a conjunction of these two 
 poisons may serve as a medium for the spread of yellow 
 fever where the germ of the disease exists, either by impor- 
 tation or by hibernation. Nothing is surer than that 
 typhoid fever is produced by animal affluvia, and if at the 
 same time a vegetable malaria, such as will produce a high 
 grade of remittent bilious fever, is prevalent, a typho- 
 malarial disease, akin to yellow fever, will be produced. 
 
 The fevers produced by an atmosphere thus corrupted, 
 have generally been stated to be produced by contagion. 
 Most authors who have observed and recorded facts similar 
 to those which have been mentioned, have represented them, 
 not as proving the power of a corrupted atmosphere to ex- 
 cite malignant fever, but as establishing its power to gener- 
 ate contagious fever. But it is obvious that they do not 
 afford the slightest evidence of the existence of a contagious 
 influence ; that the supposition of contagion is entirely gratu- 
 itous ; that the exact and only point they prove is the power 
 of a corrupted air to produce malignant fever ; that other 
 evidence is necessary to prove that the fever so produced is 
 contagious, namely, evidence that when once generated it 
 reproduces itself by contact of the sick with the healthy in 
 a pure atmosphere, and that it observes all the other laws of 
 a contagious disease. The single error of thus confounding 
 the influence of a corrupted atmosphere with the generation 
 and communication of a specific animal poison, has produced 
 
17 
 
 the most extraordinary and universal confusion of ideas on 
 the subject, and the removal of this source of misconception 
 is all that is now needful to render it perfectly luminous. 
 We hope and believe, it will be felt to be so by every intelli- 
 gent and unprejudiced mind. 
 
 There is one fever, for the especial purpose of elucidating 
 the nature of whioh, we have entered into this discussion, 
 namely, 
 
 THE YELLOW FEVER. 
 
 The point to be ascertained is, whether or not this fever is 
 contagious ; and in order to arrive at the truth, it is only 
 necessary to examine whether it conforms to the laws of con- 
 tagious or epidemic diseases. Let us then attend to the his- 
 tory of this fever with a special reference to this matter. We 
 will take the fever of Barcelona, Spain, in 1821, as a prototype 
 of the fever which prevailed in the lower Mississippi Valley 
 last autumn. Of the fever of Barcelona in 1821, Dr. Maclean 
 has given so complete and masterly an account, that in order 
 to clearly exhibit its nature, (and it may stand as a paradigm 
 of yellow fever,) it is only necessary to select from the facts 
 with which he has supplied us. 
 
 1. In the first place it appears that this disease was singu- 
 larly diversified in the forms it assumed ; that the combina- 
 tion, the succession and the degree of its symptoms were 
 so different in different cases that it was difficult to assign to 
 it any fixed and invariable progress, and that it was exceed- 
 ingly irregular in the slowness or the quickness of its course. 
 In all these respects it conformed to the first law of epidemic 
 diseases, and was in contrast with that of a contagious dis- 
 ease. 
 
 2. This fever commenced in August, that is, precisely at 
 the period of the year in which epidemics have always been 
 known to manifest themselves in Spain in similar latitudes. 
 Thus in the epidemic which prevailed in Andalusia, in 1804, 
 out of the twenty-three towns which it attacked that year, 
 it commenced in the month of August in ten, and in Sep- 
 tember in eight. The fever of Barcelona continued to in- 
 
18 
 
 crease till the middle of October ; the greatest mortality 
 took place on the 19th of that month. This is also in strict 
 conformity to the regular course of epidemics. In the epi- 
 demic of 1804, in sixteen tows in Spain, the greatest mor- 
 tality took place in the month of October ; in Cadiz, in 
 Alicante, and at Gibraltar, by a singular coincidence, it 
 took place on the same day, namely, the 9th of that month. 
 From the 19th of October the fever of Barcelona gradually 
 declined, and subsequently it continued to diminish, in a 
 regular and progressive manner, until its total disappear- 
 ance. Thus the fever conformed to the second law of epi- 
 demic diseases. 
 
 3. It appears, that in Barcelona, from the neglect of the 
 public police for many years, the sewers, drains, canals and 
 other channels for carrying away the impurities of the city, 
 had been choked up, and become foul to such a degree, that 
 towards the -end of June it was impossible to pass by the 
 sea-wall, where they were discharged into the harbor, with- 
 out being incommoded by the stench of accumulated and 
 putrifying animal and vegetable substances. A committee 
 which was charged with the office of cleansing the port, dis- 
 covered that the water course was obstructed at its mouth 
 by a bank of sand, which prevented its discharge, and, con- 
 sequently, that a large quantity of stinking water was col- 
 lected, the product of various manufactories, slaughter- 
 houses, wash-houses and other establishments situated on its 
 banks, exhaling an insufferable stench. The foul water 
 which stagnated around this sand bank was one foot higher 
 than the level of the sea. Now in the houses of Barcelona 
 which faced the port, in the streets de los Encantes, de la 
 Merced, Mencado and others adjoining the focus of infection, 
 the mortality was horrible and nearly general ; whilst in 
 the streets of Santa Anna, Tallers, San Padro, which are 
 higher, and in others which are exposed to the north, and 
 which are most distant from the focus of infection, there 
 were very few sick. At a certain elevation and at a certain 
 distance from the southeast wind, which was the conductor 
 of the noxious exhalations, as is proved by the course of the 
 
19 
 
 epidemic, not an individual sickened who had not been ex- 
 posed to the causes affecting the lower part of the city. In- 
 deed the higher parts of Barcelona enjoyed a total exemption 
 from the disease. These facts prove that the disease was a 
 true epidemic ; they are inexplicable on the supposition that 
 it was propagated by contagion. 
 
 4. Certain facts connected with the origin, progress and 
 termination of this disease, afford irresistible evidence that 
 it was an epidemic fever, and could not possibly be propa- 
 gated by contagion Thus it was common to see four, six, 
 or even eight individuals of the same family simultaneously 
 affected ; that is in the same day, the same hour, the same 
 instant. This might have arisen from an exposure to a pes- 
 tilential air, it could not have arisen from contagion. It 
 broke out in numerous points at once ; it committed the 
 most fearful ravages in certain spots, while places in the 
 closest proximity were entirely exempt from its attack. In 
 a narrow street in Barcelona called Calle de la Daguizea, 
 one hundred and thirty persons died ; in a place within ten 
 yards of it not one perished. In Barcelonetta there were 
 two families which resided close to each other — they both 
 lived about the middle of the south side of Calla Santa 
 Barbara — the houses were of the same size, plan and struc- 
 ture. The easternmost family consisted of six persons, they 
 kept a grocer's shop and were in constant communication with 
 the public — here not one was sick. The westernmost family 
 consisted of ten members, they kept a wine and liquor shop, 
 and were also in constant communication with the public — 
 here every one sickened and nine died. The grocer whose 
 family did not suffer at all, was sheltered from the southeast 
 wind ; the spirit merchant's family, every member of which 
 suffered, was directly exposed to it. 
 
 These facts are in perfect harmony with the usual cause of 
 fever in this country. Of the fever in Gibraltar, in 1813, 
 Mr. Gardener, Surgeon to the Naval Hospital, observes that 
 the disease did not spread from any focus, but broke out in 
 fifty different places at once. " The rise and progress of our 
 epidemics," says Mr. Amiel, " have never been traced in a 
 
20 
 
 satisfactory manner from a single point of contagion to a 
 gradual number of individuals or families ; and instead of 
 creeping slowly from one district to another, cases have made 
 their appearance unconnected and scattered at different 
 points ; and in some instances it has spread with the rapid- 
 ity of the electric fluid, attacking persons who had never 
 approached the sick or any assignable cause of conta- 
 gion." 
 
 Like other epidemics, it was when the fever of Barcelona 
 had acquired its greatest degree of extension, and produced 
 its greatest mortality tbat it began notably to decline. That 
 day, as has been stated, was on the 19th of October ; on that 
 day there died two hundred and forty-six persons, on the 2d 
 of November there died only ninety-eight; subsequently it 
 diminished in a regular and progressive manner until its 
 total disappearance. 
 
 When those who had contracted the fever in Barcelona re- 
 moved into the country, whether they died or recovered, not 
 a single case occurred of the communication of the malady, 
 even to their nearest relative, if the latter had not been in 
 the city. Great numbers of persons passed the whole day in 
 the capital who retired at night to their families, either in 
 country houses or in the nearest villages ; in no case did 
 they communicate the disease to any individual. 
 
 The danger, so far from being in the direct ratio of inter- 
 course with the sick, was in many instances in the inverse 
 ratio. Whenever the hospitals were placed in healthy situ- 
 ations, the attendants on the sick, in these establishments, 
 enjoyed even a greater exemption from disease than the in- 
 habitants of the town generally. The average proportion of 
 persons who were sized, estimated upon the whole commu- 
 nity, was about one in seven. In the Geneial Hospital, the 
 proportion of those who sickened among the attendants was 
 also one in seven ; in the Lazaretto of the Vice Queen of 
 Peru, it was one in eight ; in the Hospital of the Seminoria, 
 it did not exceed one in thirty ; in the Lazaretto of Naza- 
 reth, which was the receptacle of the worst cases, there were 
 thirty attendants upon the sick ; of these not one was seized. 
 
21 
 
 Surely this is evidence which no mind can resist that the dis* 
 ease was not contagious. 
 
 Several families isolated themselves in their houses, and 
 employed the most exact precautions for avoiding communi- 
 cation with the sick ; but they did not by any means pre- 
 serve themselves from the malady. Those who shut them- 
 selves up in good air, and who possessed the means of sur- 
 rounding themselves with the conveniences and comforts of 
 life, were uniformly exempt from the disease ; those who 
 shut themselves up in the pestilential atmosphere, and who 
 had not the means of rendering their condition comfortable, 
 were sooner affected than those who mingled in indiscrimi- 
 nate intercourse. These facts afford the most irresistible 
 evidence that this fever is a true epidemic. It conformed in 
 every respect to the laws of epidemic diseases ; it is without a 
 single character of a contagious disease. So complete is this 
 evidence that it produced the fullest conviction in fifteen phy- 
 sicians who assembled from all parts of Spain and of Europe 
 to investigate the disease, and it produced a practical con- 
 viction in the Spanish Cortes, contrary to all their ancient 
 and deep-rooted prejudices, notwithstanding the fact that 
 they had so recently witnessed the appalling extension and 
 the horrible mortality of the disease. In the United States, 
 Dr. Kush, who had been a warm advocate for the doctrine 
 of the contagious nature of yellow fever, on a more patient 
 and strict examination of its phenomena and history, became 
 convinced that he was in error, and with a magnanimity 
 which has but few parallels in the medical profession, pro- 
 claimed to the world that he had thought and written on 
 this very important subject in a manner calculated to mis- 
 lead. " In the fouth volume," (Medical Enquiries and Ob- 
 servations,) says this celebrated physician, u the reader will 
 find a retraction of the author's former opinion of the yellow 
 fever spreading by contagion. He begs forgiveness of the 
 friends of science and humanity, if the publication of that 
 opinion has had any influence in increasing the misery and 
 mortality attendant upon that disease. Indeed, such is the 
 pain he feels in recollecting that he ever entertained or prop- 
 
agated it, that it will long and perhaps always deprive him 
 of the pleasure he might otherwise have derived from a re- 
 view of his attempts to fulfil the public duties of his sta- 
 tion.' ' With such evidence before us, it is impossible to re- 
 sist the conclusion that the yellow fever is an epidemic and 
 not a contagious disease. 
 
Contagious ^> Epidemic Diseases 
 
 CONSIDERED WITH REFERENCE TO 
 
 Quarantine and Sanitary Laws 
 
 IS YELLOW FEVER CONTAGIOUS ? 
 
 B -y- 
 
 C. W. CHANCELLOR, M. D. 
 
 Late Professor of Surgery in the Washington University, Baltimore ; 
 
 Secretary of the State Board of Health of Ma 1 .; Member of 
 
 the American Public Health Association ; Editor of 
 
 the "Sanitary Messenger" &^c, &»c, &*c. 
 
 BALTIMORE: 
 
 JPTZX^^^^Z^ ET JOHN COX, 
 Corner Pratt Street & Spear's Wharf. 
 
 1JB7*. 
 
LIBRARY OF CONGRESS 
 
 022 194 844