_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.