tions of these organs and tissues which have just been given, that the lesions in this disease are numerous and profound. Its pathological anatomy corresponds, in complexity, variety, and extent, to its symptomatology. There are, indeed, few if any diseases of an acute character and of common occurrence, in which this complexity, variety, and extent of symptoms and pathology constitute so prominent and so striking a feature as in this.

Some of the lesions, as has already been said, are more or less accidental; that is, they do not necessarily constitute any part of the pathological anatomy of the disease. They are not constantly present. Many of these, however, such as the changes in the mucous membrane of the stomach, and the alterations of the spleen, are of very frequent occurrence, and, we have good reason to believe, play generally an important part in the pathology of the disease. Other lesions are not accidental, but essential-necessary to the disease. They always enter into its composition. They make up one of its constituent elements. They are invariably present. This is the case with the alteration of the elliptical plates of the small intestine, and the lymphatic glands of the mesentery, corresponding to these altered plates.

The real and relative importance of the several lesions, accidental and essential, is a question, in the actual state of our knowledge, not susceptible of absolute and positive settlement. It is a very natural and philosophical conclusion, perhaps, that the essential and constant lesions are more important than those of an opposite character. This is true, of course, so far as diagnosis is concerned; so far as the fixing and identification of the specific disease is concerned; but it is very questionable whether these lesions exert a more powerful influence upon the rapidity and the danger of the disease than some of the others. It seems, indeed, very probable that, in many cases, life is destroyed, or the disease is rendered dangerous and severe, by the successive development of these secondary alterations, rather than by the extent and gravity of the essential lesions alone.

The order of succession in which the several lesions commence and are developed is also a matter not susceptible of very rigorous demonstration. Death almost never takes place, in the disease, before the termination of the first week, and not often so early as this. Still, a careful study and comparison of the pathological appearances which are presented in cases of differing durations will enable us to arrive at a reasonably certain approximation to the

truth. There can be but little doubt, I think, that one of the first, probably the first pathological alteration which takes place in the solids, consists in the tumefaction of the elliptical plate, or plates, nearest to the ileo-coecal valve. This tumefaction is accompanied or followed by other changes-an afflux of fluids, softening of the mucous coat, the hard, yellow typhous deposits in the submucous tissue, and, finally, by ulceration; and these several lesions taking place, first in the plates nearest to the ileo-cocal valve, gradually and successively extend to those which are further removed from it. Contemporaneous, probably, or nearly so, with these alterations, are the reddening, enlargement, and softening of the mesenteric glands. The enlargement of the spleen, and the diminution of its consistence, occur, also, there is good reason to think, in the early stages of the disease; and the same thing is probably true, though less constantly, perhaps, of the softening of other organs. The various pathological changes, which are found in the gastro-intestinal mucous membrane, begin and are developed, it would seem, at uncertain and indefinite periods, during the progress of the disease.

As to the relation which exists between these appreciable lesions -one or many of them-and the disease itself, if we may so speak, I have but little to say. This is a question which is wholly theoretical in its character. Its settlement, by different individuals, will depend entirely upon the mode of interpreting the phenomena of typhoid fever, and the relations of these phenomena which they may choose to adopt. One thing, however, we may say, and that with great confidence, and without any qualification; to wit, that typhoid fever is not a gastro-enteritis. It may, correctly enough, be called a peculiar enteritis, or a dothinenteritis, but not a gastro enteritis; and this, for reasons sufficiently obvious. I do not think, however, that we are justified in referring typhoid fever, considered as a disease -as an integral, though complex, pathological condition, and process or series of processes-to this single local lesion of the intestines. I do not think that we are justified in considering the latter as the exclusive origin and cause of the former, as we consider acute inflammation of the mucous membrane of the large intestine the cause of that other disease-that other integral pathological condition and process, or series of processes-which we call dysentery. The most striking analogies are all against this interpretation. It seems to me much more satisfactory and philosophical, much more in accordance with what is seen in many other diseases, to look upon the lesion of the elliptical plates, not as the local cause of all the other

appreciable phenomena of typhoid fever, but as constituting one of the pathological elements, in a very obscure and complex disease; all which elements, and this quite as much as the others, are themselves the result of some morbific agent, or influence, or process, the nature, sources, and operation of which are wholly unknown to us.. The lesion of the elliptical plates seems to me to bear somewhat the same relation to typhoid fever, considered as a disease, as that which their several characteristic eruptions bear to measles, scarlatina, and smallpox. In none of these, have we any right to regard the cutaneous eruptions as the causes of the symptoms, and of the other various phenomena, which go to make up the several diseases themselves. I shall have occasion to refer to this subject hereafter.

CHAPTER IV.

CAUSES.

THE only causes of typhoid fever, the influence of which has been at all positively and accurately ascertained, are these three, to wit, age, recent residence in a given place, and contagion. In using the word cause here, I mean merely to express by it some of those circumstances or conditions amidst which the disease under consideration most frequently occurs. The nature and essence of the actual, producing, efficient cause of typhoid fever, as of most other diseases, are entirely unknown to us.

SEC. I.—Locality. Typhoid fever is evidently a disease of very extensive geographical prevalence. We have not the means of ascertaining its limits, but there is good ground, I think, for believing that these limits are wider than those which circumscribe the prevalence of any other strictly idiopathic, non-eruptive fever. It is the common fever of the Eastern States. It is questionable, indeed, whether this section of the country is the seat of any other fever, unless it be an occasional sporadic case, or epidemic, of an obscure and doubtful character. The extent of the prevalence of typhoid fever in the New England States may be judged of by the following statistics, derived from the bills of mortality for the city of Lowell for a series of sixteen years, from 1830 to 1846, inclusive. The entire number of deaths from typhoid fever amounted to four hundred and thirty-five. There was only one disease which occasioned a larger number, and that was consumption. The population of Lowell during this period increased pretty regularly, from 6477 to somewhat more than 20,800. The number of deaths from typhoid fever annually varied from five, in the years 1830 and 1831, to forty-four, in 1839. From 1832 to 1846, the smallest number in any single year was sixteen. This was in 1841; in the preceding year, it was twenty-six; in the following year, it was forty-three. In 1846, the mortality went up to one hundred and one. These statements serve to show, at the same time, the importance and

frequency of the disease, and the variations in the extent of its prevalence in different years. It prevails, also, more or less extensively, in the Middle and Western States. I have often seen it in Kentucky, where it is sometimes called the red tongue fever. It is probably less common in those portions of the United States which are visited by the various forms of intermittent and remittent fever than in those which are exempt from these diseases, although more extensive and accurate observations than have yet been made are necessary to settle this point. Now that the means for correct and positive diagnosis of the several distinct fevers of our country are becoming more and more generally diffused, there is reason to hope that this, as well as some other circumstances in the natural history of typhoid fever, will soon be satisfactorily established.

In December, 1846, I addressed letters to the editors of the medical journals, published in the Southern and Western States, inquiring particularly as to the existence, in their respective neighborhoods and regions, of typhoid fever. These letters have been promptly and kindly noticed, and they demonstrate very conclusively the prevalence, more or less extensive, throughout many portions of the Southern and Western States, of genuine typhoid fever, its symptoms and lesions corresponding exactly to the common continued fever of France and New England. The interest attaching to this subject induces me to make a few extracts from this correspondence.

Dr. Mattingly, of Bardstown, Kentucky, says that typhoid fever prevailed extensively in that town during the fall and winter of 1846. He enumerates the following phenomena as very constantly present in cases of moderate severity: "Chills; increased local or general heat; accelerated pulse, generally about 100; loss of appetite; muscular debility; more or less diarrhoea; pains in the bowels; dulness of the intellect; more or less delirium; frequent epistaxis; dry, brown, or red tongue, trembling, and with difficulty put out of the mouth; rose-colored spots, or typhoid eruption; twitching of the tendons; a purplish flush on one side of the face, passing over to the other in the course of two or three hours; a greater or less degree of tympanites; somnolence, or watchfulness; ringing in the ears, or deafness; one or two exacerbations of fever every day, constantly in the evening, sometimes in the forenoon. These symptoms come on gradually, increasing in violence from

1 An Address before the Mass. Med. Soc. By John O. Green, M. D.