THE ORIGIN OF YELLOW FEVER.

YELLOW FEVER has been the subject of some of the most violent controversial storms that have ever ruffled the surface of medicine. Whether the fever was contagious or non-contagious, whether it was imported or bred on the spot, whether it was a peculiar kind of specific fever, or only a severe form of malarial fever, these are some of the questions that have been hotly debated, and nowhere more hotly than among the medical men of Philadelphia, in the life-time of the great Dr. Benjamin Rush. It is now possible to look at these controversies in the perspective of history, and fortunately it is possible for most of the Atlantic cities of the United States so to regard the disease itself. The discussions as to its nature and origin and its mode of conveyance are no longer in the acute stage of violent and irreconcilable antagonisms. The air is cleared, and the chaos has fallen into something like order; and if there are still various hypotheses of the origin of the fever, there is almost complete agreement as to all its associated circumstances, or its natural-history characters among the species of disease. No single work has contributed so much to the modern disentanglement as the two volumes of elaborate inquiry and dispassionate statement brought out by Dr. La Roche, of Philadelphia, in 1855, a work that reflects the highest credit on American scholarship and research.

But, although Dr. La Roche has carefully gone over the whole ground, and sifted and scrutinized everything that has turned up, through sixteen hundred closely printed pages, it appears to my humble judgment that he has somehow never caught the sparkle of the gem that he was seeking for. The secret of yellow fever, it seems to me, is contained in the almost forgotten essays of Audouard. La Roche quotes the title of these among the innumerable other books and pamphlets; but I

find nowhere in his pages any evidence that he had mastered the facts of Audouard's argument, or duly weighed its conclusions. Dr. Audouard failed to secure the imprimatur of the French Academy of Sciences for his various essays on yellow fever, and the neglect of them is one more illustration of the fact that the world is too busy to form its opinion at first hand on a question. My attention to Dr. Audouard's theory of yellow fever was first attracted by finding it described in Prof. Hirsch's well-known treatise on Geographical and Historical Pathology, which was then coming out in English, as eine der abenteuerlichsten Hypotheseis. Stimulated rather than deterred by this damaging epithet, I procured the book from the library of the Royal Medico-Chirurgical Society of London. The library owed its copy to the mindfulness of the author himself, according to an autograph letter pasted within the cover, and bearing date, April 11, 1825.

Dr. Audouard's letter, a folded quarto sheet, now yellow with age, is a well-written appeal to academical medicine in England to give its best attention to the very serious facts that he had discovered when inquiring officially into two of the Spanish epidemics of yellow fever in 1821 and 1823. At Barcelona and Passages respectively, in these years, it had struck him with peculiar force that the fever had issued from the holds of ships that had been employed in carrying negro slaves from the west coast of Africa to Havana, and had returned to Spain with West Indian produce.

"Cette conformité d'origine dans deux cas différens, me porta a faire des recherches à la faveur desquelles j'ai trouvé le moyen d'expliquer tout ce qui, jusqu'à present, avait été obscur et inexplicable. . . Ces memoires contiennent des idées nouvelles auxquelles je n'en doute pas, vous ne refuserez pas votre attention; et si elles vous paraissent propres à seconder les vues de votre gouvernement relativement à la traité des noirs, vous vous en expliquerez franchement afin de vous montré favorable à l'humanité d'une double maniere, savoir; en travaillant à abolir l'esclavage des noirs, et en preservant la race blanche de la fièvre jaune qui est le resultat de ce trafic "

Like every one who trusts to ideas making their way by their inherent force, Dr. Audouard was much too sanguine when he wrote: "Je n'en doute pas, vous ne refuserez pas votre attenIt soon became apparent, as I proceeded to glean the "idées nouvelles," that not one officer or fellow of the society in all those years had taken the trouble to cut the leaves. The fact

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was, the terrible yellow-fever epidemics that ravaged the Spanish ports and threatened the rest of Europe in the beginning of the century were already over, and Europe was all the more ready to forget its danger from the Western pestilence in its preoccupation with a new enemy, the cholera. But the interest in yellow fever is still real for the Western Hemisphere, and it seems to me to be desirable for both theory and practice that Dr. Audouard's facts and reasoning should receive full attention.

If we take a sketch-map of the world and color on it the places where yellow fever has been most prevalent at one time or another, we shall find that they group themselves in a very significant manner. The whole continent of Asia, the cradle of so many great pestilences, takes no share; Africa does not concern us, except for two or three small spots on the western coast; no part of Europe has to be colored in, except certain ports of Spain and Portugal. Our spots of color are nearly all on the American side of the Atlantic, and they are but minute points on the coast. Yellow fever is a pestilence of certain shipping-places, and particularly of their harbors, wharves, and sailors' quarters. Now and then it has penetrated beyond the sea-port or the banks of a navigable river, as in the great epidemics in Spain in the beginning of the century; but the circumstances were those of exceptional virulence of the poison and exceptional panic among the people, and they serve rather to show how remarkably uniform the behavior of yellow fever has been, on the whole. While Barbadoes and Antigua have a healthy climate, Bridgetown and English Harbor have been notorious for the epidemic of yellow fever. It is not all Cuba, but Havana; not all Hayti, but Port au Prince; not Martinique, but Port Royal; not South Carolina, but Charleston; and not Pennsylvania, but Philadelphia.

Putting together these singular facts of geographical distribution, and adding what we know of history, we are led to the conclusion that the ports of yellow fever are mostly the old ports of debarkation in the slave-trade, the first authentic epidemics having occurred shortly after the first arrivals of slaveships in the West Indies. The pestilence first showed itself at Bridgetown in 1647, twenty years after the English began to plant there; and we know from an authentic document that in 1650 there were at that place flourishing sugar-plantations well stocked with negroes. The "new disease" took every one by surprise. It

was "an absolute plague, very infectious and destroying," says Mr. Vines, writing to Governor Winthrop, of New England, “insomuch that in our parish there were buried twenty in a week, and many weeks together fifteen or sixteen." Mr. Vines thought it was a punishment for the sins of the people, that it was "the Lord's heavy hand in wrath"; and Captain Ligon, who came out from England while it was raging, believed that it was somehow connected with the arrival of ships. The "Pere Dutertre" says it was "une peste jusqu' alors inconnue dans les isles," and that it carried off one-third of the inhabitants of St. Kitts in eighteen months. During the two centuries following, it has become endemic at many ports, and these are the places at which slaveships have either discharged their negroes, or gone in ballast or with merchandise on the round voyage. The one considerable exception is the Peruvian coast, where yellow fever appeared first in 1853. I am prepared to deal with that exception and with others, if space permitted; but it must suffice to say here that the people of Callao, for some reason, blamed the arrival of filthy ship-loads of Chinese coolies, who had suffered terribly from dysentery; that the Chinese in Lima are said to be almost as much protected against yellow fever as the negroes on the Atlantic side; and that the Chinese coolie trade, from 1847 to 1856, was carried on by "ships badly equipped and overcrowded, and on their voyages they reproduced all the horrors of the 'middle passage' in the old African slave-trade."-("Encyclopædia Britannica," Article "Coolie.")

If the association of yellow fever with the ports of debarka tion of the slave-trade were absolutely invariable, I should regard it as a suspiciously neat result. A certain small margin of exception is a healthy sign in any hypothesis. The broadly impressive fact remains that yellow fever has been, both in place and in time, a close attendant on the slave-trade; that it has followed its rise and its decline at a given place, although it has survived longer at some points than at others; and that its exacerbations have coincided with the most lawless period of the traffic. What is the meaning of this association between the importation of slaves and yellow fever at the ports of debarkation, between the horrors of the "middle passage" and the after horrors of the landing-place? It is no other than the ancient association between filth and fever; but there is something quite peculiar both in the filth and in the fever.

In the first place, we have to observe that negroes on board slave-ships do not appear to have suffered from yellow fever. Whether any part of the enormous mortality among the white crews of slavers was due to yellow fever, we never shall know. These things were kept conveniently dark, and it took all of Clarkson's persistence to find out that there was any excessive mortality at all. What took place on board slave-ships on the "middle passage" is now as far beyond the reach of exact research as the slave-trade itself is beyond the possibility of revival. But we have several interesting experiences, or undesigned experiments, of the contact of white men with a shipful of negroes, ⚫ which happened under circumstances that could compromise no one, and have been authentically entered on the medical record. One of these occurred to the late Dr. James Copland, author of the "Dictionary of Practical Medicine," and it sufficed, along with observations made subsequently, to start Dr. Copland's mind in the train of reasoning that Audouard was to follow independently a few years later. He says:

"A small vessel, in which I was a passenger, was anchored, in May, 1817, a short distance from Sierra Leone; and the ship's boat, with four of the crew, was bringing me on board, when, a tornado suddenly overtaking us, we took shelter on board a ship recently brought into the harbor full of slaves, and near which we were at the time. The men belonging to the boat took shelter down between decks. I remained under a small poop on the quarter-deck. All these men in two or three days were seized with this distemper [yellow fever], the vessel having just put to sea, and I escaped. The sick men were constantly kept on deck, free ventilation was enforced, and every possible precaution used, and no more were attacked. The organization of the negro, and the more extensive functions of the skin of this race as an excreting organ, give rise to the most offensive and foul state of the atmosphere when numbers of this race are confined in a limited space, and particularly in a humid and warm atmosphere. Indeed, nothing can be imagined more nauseous and depressing than the respiration of the air so contaminated; and it may further be admitted that it so affects the organic nervous system and the blood as to develop this pestilence. The above fact, these considerations, and various occurrences or outbreaks of this distemper after communications with slave-ships that have come to my knowledge, induce me to attach some importance to this source of the evil, and to suggest that some endeavor should be made to ascertain the amount of credit it may deserve. If this opinion as to the probable origin of the infectious poison be not admitted, there is certainly none other deserving greater confidence, and we are left entirely in the dark as to the earliest origination of the mischief."

Dr. Copland's suggestion of direct contact with a crowd of negroes goes only a little way, as he was himself aware; it