While it is true that typhus fever is not usually accompanied by active gas tro-intestinal irritation, yet exceptional cases occur during almost every epidemic characterized by active diarrhoea and vomiting. On the other hand, cases are occasionally met with in which constipa tion requiring the use of laxatives per sists throughout the whole course of the disease. Such eases are generally char acterized by much delirium or stupor and subsultus.
Diagnosis.—The diseases with which typhus fever has been most frequently confounded are typhoid, or enteric fever; cerebrospinal, or spotted fever; malig nant rubeola, and some cases of acute miliary tuberculosis. The fact that, through all the centuries prior to about the middle of the present, all cases of what are recognized now as typhoid and typhus fevers were regarded as only varieties of one type of continued fever is sufficient evidence of a close similarity in the clinical phenomena presented by them. The chief clinical diagnostic feat ures are that in typhus the prodromic stage is short; the chill or cold stage is more marked, followed by a more rapid rise of temperature without morning re missions during the first week, and a more marked crisis near the end of the second week. The pulse is more fre quent; the pains more severe in the first stage. There is more delirium, stupor, and subsultus, with but little or no diar rhoea or abdominal tympanitis. Much diagnostic importance has been attached to the character of the eruption, which, in typhus, generally appears on the ab domen and chest between the third and fifth days of the fever, and is papular or petechial in form, much resembling the eruption of measles. It does not entirely disappear under pressure, extends in many cases to the neck, face, and ex tremities, and in severe cases becomes hfernorrhagic. It differs from the erup tion in measles by appearing on the ab domen and chest first instead of the face and neck, and by the absence of the catarrhal symptoms so prominent in measles.
The characteristic eruption appears in typhoid fever in the form of rose-colored lenticular spots, from which the color wholly disappears by pressure and is not distinctly papular in any stage of its progress. The diagnostic value of the eruptions in these fevers is much less ened from the fact that in many cases of typhus an eruption of dark-red or pur plish spots appear in advance of, or in terspersed with, the more papular clus ters, and in rare cases impart to the sur face an erythematous appearance. It is these maculte that most resemble the eruptions in cases of cerebrospinal fever. In many cases the eruptions are so inter mingled as to leave the most experienced observers in doubt as to the true diagno sis during the whole progress of the dis ease. [See cases recorded in "Clinical Reports on Continued Fever," by Dr. Austin Flint, 1S52; and by Dr. J. M. Da Costa in American Journal of Med ical Sciences, p. 1, July, 1899.] Again,
not a few cases, especially of the milder class, have been met with in which no eruptions of any kind were observed. MM. Louis and Charnel and their fol lowers endeavored to found the diagnosis between typhoid and typhus fevers largely on the abdominal symptoms and pathological changes in the glands of Peyer and the mesentery. The presence of tympanites and gurgling on pressure with liquid stools was regarded as strongly indicative of typhoid; and in fatal cases if the post-mortem revealed tumefaction and ulceration of Peyer's glands in the intestine and enlargement of the spleen and mesenteric glands the _diagnosis was regarded as complete. The recently discovered Vidal reaction, or test, was at first thought to he peculiar to the blood serum of typhoid fever, and therefore valuable in differentiating that disease from typhus and other forms of fever. Further investigations, however, have shown the presence of that reaction in the blood of typhus, yellow fever, and the plague, while it can be obtained in typhoid cases often only after the first week, and in the most severe cases not at all. It is perhaps valuable as indicat ing the beginning of immunity, and therefore prognostic in its import.
Etiology.—Typhus fever is very gen erally regarded as a highly contagious affection. But, up to the present time, neither the chemist nor the bacteriologist has been able to identify any specific toxic agent as the essential cause of the disease. Its whole previous history has shown it to be closely connected with populations living in overcrowded, un cleanly, and ill-ventilated houses, camps, prisons, almshouses, and ships, and with insufficient food. Some of the most ex tensive and destructive epidemics of the disease have followed directly in the wake of famine. This is well illustrated by the history of its prevalence in Ire land and in the countries bordering on the Baltic sea. During the middle part of the present century, when many thou sands of immigrants to this country from Ireland and other parts of Europe were crowding almost every sailing vessel that crossed the Atlantic, typhus fever was so prevalent among them that it became generally known as and so filled the quarantine and emigrant hos pitals in New York and Boston as to greatly increase the ratio of mortality. But the subsequent rapid and almost complete transference of all immigrant and other passenger traffic from the slow sailing vessels to the fast moving ocean steamships has resulted in nearly ban ishing the "ship-typhus" from the ocean as well as from our important sea-port towns. This change in the ocean travel coincident with extensive improvements in the sanitary condition of most of the great centres of population, both in this country and Europe, has rendered typhus comparatively a rare disease during the last twenty-five years.