In view of the general disregard of direct observations, it is therefore not surprising to learn that the nature of the intestinal lesions gradually fell into oblivion or at least became underrated in its import. But it is a matter of surprise that Stoll (1780) was able to declare as the result of autopsies made by himself that, although the colon is thickened and inflamed, ulcerations in dysenteries are very rare. This distinguished author did not at all believe in the contagion of the disease, as he had never seen it attack physicians or nurses. It developed, he thought with the older writers, as the result of exposure to cold during a perspiration. He emphatically insisted upon the frequency of rheumatism as complicating the disease, and describes in proof a number of cases of painful swollen joints during and subsequent to the attack. It was his especial merit to have succeeded in dispensing with the acrid bile as a cause of the disease, maintaining that hepatic derangements were only accidental complications, and thus disposed, but only for a time, of bilious dysentery in so far as it was supposed to depend upon defective or abnormal action of the liver.
But Annesley (1828) soon reinstated the liver in the pathology of dysentery, with the exhibition of colored plates displaying abscess of the liver in connection with the disease, as well as illustrating the displacements and constrictions of the colon which sometimes occur in its course.
The fourth decade of our century now brought in the anatomical contributions of Cruveilhier and Rokitansky, to be followed later by those of Virchow, upon which the modern morbid anatomy of the disease is based; while the labors of the Indian physicians and of Copeland, Parkes, and Vaidy put us in possession of the facts pertaining to its general pathology. Fayrer has quite recently published the results of his vast experience with dysentery in India, an important contribution to the practical study of the disease, and Hirsch has treated exhaustively of its medical geography. But the merit of publication of the most complete chapter or work upon dysentery that has ever been written anywhere belongs to, and is the especial pride of, our own country. It constitutes the bulk of the second volume of the Medical and Surgical History of the War of the Rebellion. It is a veritable encyclopædia of knowledge, not only upon the subject of which it treats, but upon all subjects immediately or even remotely collateral to it, and is a lasting monument to the labor and the learning of its author, Joseph J. Woodward, Surgeon of the United States Army.
GENERAL REMARKS.—Dysentery may be a primary or a secondary disease. As a primary disease it occurs in sporadic, endemic (often closely, sometimes curiously, circumscribed), or epidemic form, and is either acute or chronic, according to the nature of its symptoms and lesions. The ancient types of sthenic and asthenic or adynamic, typhoid, bilious, and malarial dysenteries belong rather to history than to modern medicine. The classification of cases in general use at present—viz. the catarrhal and croupous or diphtheritic forms—has reference rather exclusively to the nature of the lesion, and is hence extremely defective. Nor are the divisions (as in cholera) into sporadic and epidemic forms much more satisfactory, in that they indicate simply the range or extent of the disease, and by no means define a separate array of symptoms or lesions; precisely the same symptoms or lesions being encountered in individual cases of either form. None of these divisions clearly indicate differences in etiology, upon which factor alone can any acceptable division of cases be based. Perhaps less objection may be urged against the assumption of catarrhal and specific forms, including under the provisional term catarrhal all the cases which cannot as yet be accounted for by the action of a special or specific cause.
It will become apparent in the study of the etiology of dysentery that while any of the factors invoked may suffice to produce the catarrhal (sporadic) form, none will explain the specific (epidemic) form of the disease; both forms may be alike in their lesion and signs, but they differ widely in their cause. In other words, dysentery is only a clinical, and is in no way an etiological, expression of a disease. In this respect dysentery finds its analogue in a much grosser lesion of the bowels—namely, occlusion, acute or chronic, which, while it presents pretty much the same train of symptoms, may depend upon a great variety of causes, as impaction, strangulation, intussusception, etc. While any of the causes cited may be sufficient to excite the catarrhal form of the disease, the same causes may stand to the specific form only in the relation of predisposing agents. Or, as Maclean has better put it, "It appears that many of the so-called causes of dysentery must be regarded more as acute agents of propagation than of causation."
As a secondary disease dysentery occurs in the course of, or as a sequel to (not infrequently as the terminal affection of), pyæmia and septicæmia (puerperal fever), typhus and typhoid fevers, pneumonia, Bright's disease, variola, scarlatina, abscess of the liver (though the order of sequence is here oftener reversed), scorbutus, marasmus from any cause, tuberculosis, and cancer. It must not be forgotten, however, of these latter affections that each produces its own lesions in the large intestine, which are not to be confounded with those of genuine dysentery.
The view that dysentery shows a periodicity of recurrence at certain distinct intervals or cycles—three, five, or ten years—is entirely without foundation in fact; but there is strong ground for believing that the disease is gradually abating both in frequency and virulence with improvements in sanitation and hygiene. Thus, Heberden shows that the number of deaths set down in the seventeenth century under the titles of bloody flux and gripings of the guts was never less than 1000 annually, and in some years exceeded 4000, whereas during the last century the number gradually dwindled down to 20 (Watson)—a number which is certainly a misprint for 200; and Aitken states that as a cause of death it has been decreasing since 1852. Geissler also remarks1 that the variation in epidemics is nowhere so well illustrated as in the case of dysentery. A noticeable reduction in the number of cases in England began about 1850, and has continued almost without interruption to the present time, so that now (1880) six to eight times less cases occur than in the forties. The same diminution has been noticed in Bavaria and Sweden. In Sweden the cases treated by physicians in 1857 numbered no less than 37,000, with over 10,000 deaths; whereas now the number is reduced to 400-500 a year, and the mortality has experienced a corresponding reduction from 20-30 to 6-8 per cent.
1 Periodische Schwanderungen der wichtigsten Krankheiten.
At the same time, it is known of dysentery that it sometimes shows an almost freakish recurrence after long intervals of time, appearing in a place for many decades free from the disease, to establish itself there for years as a regular endemic malady, not to disappear again for a long series of years; in which respect, Hirsch remarks, it much resembles malaria.
Allusion has been already made to the occasional curious circumscription of the disease in definite localities. In fact, dysentery, even when late to assume the proportions of a widespread epidemic, begins, as a rule, and is confined for a time, in individual enclosed regions—prisons, barracks, hospitals, etc.; and in the process of dissemination it is rather characteristic of the disease to leap over or to spare intervening territory and appear in new foci at some distance from its original seat. A direct irradiation or linear transmission of the disease is the exception, and not the rule. The significance of this fact will become evident in the study of the etiology of the disease.