Prognosis.—As regards the prognosis in yellow fever, I shall merely state, that I generally found, an early evacuation from the alimentary canal, and a disposition to diaphoresis during the first twenty-four or thirty-six hours, and its continuance during the course of the disease, to be favourable omens. When the disease continued beyond the 7th, 9th, or 11th day, greater hopes might be entertained. It was likewise found, that the mortality was much smaller among patients, who remained free from apprehensions as to the nature and termination of the disease. To this cause, more than any other, do I refer my greater success among Quakers; who, being generally surrounded and comforted by their friends, retained more than any other class of people, the necessary tranquillity of mind.
Among the unfavourable signs may be mentioned, a discoloration of the skin before the fourth day. This symptom was, indeed, almost always a fatal one. Obstinate vomiting and costiveness, hæmorrhages from different parts of the body, unattended with an abatement of the symptoms, and vomiting of black matter, were very unfavourable; whilst a suppression of urine, agreeably to my experience, was always a fatal sign.
Black Vomit.—In a preceding part of these observations, in alluding to the black vomit, I took occasion to express my views respecting its nature,—stating that I regard it as consisting of mucous flakes, mixed with a large proportion of altered blood. That such is the true nature of this substance, on which so much has been said and written, I have had sufficient reason to be convinced. The opinion that it consists of altered bile, I deem totally untenable, for the following reasons: The matter is occasionally voided in large quantities, in cases in which the liver is not at all affected, and in which, after death, the gall bladder is discovered to be more or less filled with natural bile. Independently, of this, it may be stated, that the appearance of the two substances is very dissimilar;—the black bile vomited in bilious fever being of a homogeneous nature, and of a black or deep green colour; whilst the matter of the black vomit is, in a large majority of cases, a compound of a mucous, flaky substance, and a sanguineous matter, bearing some resemblance to the grounds of coffee, and, for the most part, of a brown tinge. When mixed with water, the two substances produce very different effects,—the bile mixing with and imparting a greenish tinge to it without difficulty, whilst the grounds of the other, float on the surface of the water, without mixing with and colouring it, in the same manner as bran, deprived of all its mucilage, or rather like mahogany saw-dust. This I consider as one of the best modes of distinguishing these two substances,—serving at the same time to establish a difference between the fevers, I was in the habit of observing in the West Indies, and the yellow fever of this country. Nor are these the only reasons for rejecting the supposition of the black vomit of yellow fever being of a bilious nature; for I have known this substance (and I suppose other practitioners have observed the same fact) occasionally to exude from surfaces, from which, in all probability, bile is excluded. I allude particularly to the skin and verous membranes. Thus it has often happened, that the application of a blister, especially in the advanced stage of the disease, has been followed by a copious exudation of a fluid, resembling, in all respects, the matter ejected from the stomach; an occurrence which was strikingly exemplified in a case, which fell under my immediate observation during the last visitation of the disease in this city, in 1820. During the same epidemic, I had occasion to attend a Mrs. H. about 70 years of age, who presented a curious example of the exudation of a similar substance from the peritoneum. She had not been exposed to the causes of the yellow fever, and indeed presented none of its ordinary pathognomonic signs. She was attacked very early in the morning with violent colic, attended with fever, great tenderness of the abdomen, and high colour of the face. She was bled at 10 o'clock; at 11 vomited a large quantity of coffee ground matter, and died in about 12 or 15 hours from the commencement of the attack. The next morning her body was examined in the presence of several highly respectable and experienced physicians, who all coincided in the opinion, that the matter vomited and which continued to be discharged from the nose, was identical with that discharged in yellow fever. The stomach as well as the intestines were found to contain a large quantity of a similar substance. The cavity of the peritoneum being likewise found filled with a large portion of it, we at first suspected the existence of an opening in the intestines, by which an effusion had taken place. After a careful and minute examination, however, no such opening was discovered. Our attention was now directed to the condition of the peritoneum itself, which was highly inflamed. It was, moreover, found, that the substance in question exuded from its surface,—the membrane, in many places, especially the portion of it which covers the liver, being coated so thickly with the grounds, that they could readily be scraped off with the back of a scalpel.
These cases show conclusively, that the matter of the black vomit, occurring in yellow fever, should not be regarded as altered bile; and that the supposition of its consisting of a secretion of the mucous membrane of the stomach, does not rest on a much more solid foundation. For bile can hardly be admitted to exude from the skin and serous membranes, and we cannot suppose, that fluids, similar in every respect, can be secreted from two surfaces, so very distinct in their organization, and in the nature of their ordinary products, as those of the mucous and serous membranes.
From these facts I am led to regard the black vomit as a true hæmorrhage, resulting from a state of previous irritation of the surface which furnishes it. That inflammation may be cause of it, we have a sufficient proof in the fact, that a similar fluid is occasionally vomited in cases of puerperal fever, when the irritation progresses from the serous to the mucous membrane of the intestines; as well as in cases of inflammation from blows on the stomach, and the action of poisons. A case of this kind, arising from a kick of a horse, was attended by myself and two respectable physicians in consultation, a few years ago; and another case arising from a large dose of carbonate of potassa, swallowed by mistake, occurred in my practice not long since. But as it would occupy too much time to give them here in detail, I pass them by without further notice.
That the matter of the black vomit is the product of a hæmorrhage, I have thought may also be inferred from the fact, often noticed by myself and others, of large portions of coagulated blood being found in the intestines; the surface having the appearance of the common black matter, whilst on cutting into them, the centre is found to consist of a red solid coagulum. I have also sometimes noticed, that the duodenum contained the coffee ground matter, and the intestines, coagulated blood. In such cases, in order to adopt the opinion of secretion, we must believe, that the same vessels, occupied in the secretory process, afforded, at the same time, passage to a portion of common blood; for we can hardly admit, that the mucous follicles are the organs secreting the black matter. Besides, is this not a mere dispute about words; and is it proved that what are called sanguineous secretions are not the result of the same action, which gives rise to hæmorrhagic exudations? and is there any other difference between the hæmorrhage of yellow fever, and of ordinary cases of hematemesis, than that arising from a difference in the quality of the blood?
Nor do I find much difficulty in believing, that the colour of the skin, which is more frequently brown than yellow, as well as the petechiæ, &c. are the effects of the stagnation of blood, altered by the capillaries of the surface, in the same manner as that exuding from the mucous surfaces. I believe that this opinion, suggested by some European writers, is supported by the fact, that this fluid exudes from the orifices made by the bites of leeches and the incisions of scarified cups; as well as from the raw surface occasioned by blisters; and that the vibices contain a serous fluid mixed with blood.
Analogy to Plague.—On comparing the symptoms of the yellow fever of this country with those of plague, as detailed so minutely and, I believe, accurately by authors, and especially by the physicians who accompanied Bonaparte to Egypt, I have been led to regard these diseases as bearing a closer analogy to each other than has hitherto been admitted. I do not pretend to assert that they are the same disease, but only that they are so nearly allied, as on some occasion, to lead even an experienced observer into an error of diagnosis. The great difference between them consists in the frequency of the affection of the lymphatic glands in the plague, and its comparative rareness in yellow fever; and in the greater predominance of gastric symptoms in the latter. Nevertheless, I have had, on many occasions, during our different epidemics, opportunities of noticing buboes, situated in the same parts as those mentioned by writers on the plague, running the same course, and curable by the same means. Carbuncles are frequently seen in both diseases, though not so frequently in yellow fever as in the plague. Both diseases present what are called the walking cases. Patients in both, though more frequently in yellow fever, retain their muscular strength as well as their intellectual faculties. So far as we are informed, the mortality in both is pretty nearly the same, and the treatment similar.
Contagion of Yellow Fever.—The question of the contagion or non-contagion of yellow fever has so long occupied the attention of the profession and been discussed so extensively, that I deem it unnecessary to devote much space to it here. Nevertheless, as I have had frequent opportunities of noticing the disease under all circumstances; in all parts of the city, and in the country; among the wealthy and the poor, I may without much impropriety offer, in a few words, the result of my observations and reflections on this head. I must unhesitatingly declare, that, establishing my opinion on what I have seen, I am led to the conviction, that the yellow fever is not a contagious disease; that it never has been carried hither in the way mentioned by contagionists; and that it has invariably proved an infectious disease, using this word to express a malady arising from a local source of contamination, other than a living body. It is plain, that this view of the subject does not exclude the possibility of a vessel carrying the disease to this or any other port; but, in that case, the vessel itself or its cargo, must be the source of infection, and not the individuals on board. And this may take place, when the port from whence the vessel sailed is free from the disease. That such has been the case, there cannot be any doubt; and that the idea, predicated on it, of the contagiousness of the fever is erroneous, I have not the least hesitation in believing.
How else than on the principle of infection, and not of contagion, can we explain the attack of individuals frequenting those parts of the city, where the disease had originated, and which (all the inhabitants having been removed to some distant situation) had been barricaded? How could we, in any other way, account for the exemption from the fever of individuals, who, out of the infected district, nursed, touched, and even slept with their diseased relatives and friends; and not always in clean and well ventilated apartments and parts of the city; but, in very many instances, in the filthiest hovels, and alleys, and among the lowest classes of society. Striking and unanswerable facts of the sort have frequently presented themselves to my observation, during our various epidemics. Children have sucked their parents, affected with the fever, and, in one case which fell under my notice, the child continued attached to the breast after its mother's death; and in all such instances with impunity. I have constantly reprobated the practice of burning the clothes and bedding of the dead, and have never found any bad results to occur to those who followed my advice. From a consideration of all these facts, I must once more express it as my decided opinion, that the yellow fever, so far as I have had an opportunity of observing it, is not a contagious disease.