CATARRIIAL DYSENTERY. — This is a disease of the intestines, affecting princi pally the large bowel, which occurs spo radically or epidemically. It is the form of dysentery met with most frequently in temperate climates.
Morbid Anatomy and Etiology.— The area of intestine involved may be large or small; sometimes the affection is limited to a circumscribed area or areas, at others the mucosa in its entire extent is in volved, even including the stomach. The colon is most often the seat of the lesions. Woodward questioned the existence of an isolated affection of the small intes tine, while Nothnagel claims to have met with cases in which the pathological process stopped abruptly at the ileo cmcal valve, the large gut having entirely escaped. The general mucosa and the solitary lymphoid nodules, especially, are affected. In the acute stage the affected part of the mucous membrane is red dened, especially about the lymphoid nodules and plaques, and small extrava sations of blood may appear. There is an excessive production of mucus and a rich desquamation of epithelial cells. The villi and solitary nodules are swelled, the latter becoming unduly prominent. The microscopical picture agrees with the macroscopical appear ances: there is hyperfernia, swelling, and desquamation of epithelial elements and round-celled infiltrations of the mucosa. The swelled lymphoid nodules show an increase in cells, the chief ones being of the large epithelioid variety occupying the germinal centres. Extravasations of blood are present in the mucosa about the nodules. The submucosa shows changes only in the severest grades. In more protracted cases ulceration, limited to the nodules or extending into the ad jacent mucosa, appear. The chronic cases are characterized by pallor of the general mucous membrane; pigmented spots appear, and at one time the mucous membrane is atrophic, at another hyper trophic. In the latter instance, in the most marked cases, a polypoid condition of the affected mucous membrane may exist.
The causes of this disease are twofold, namely: agents of (A) intoxication and of (B) infection. (A) All caustic chem
ical agents which act directly upon the mucous membrane (acids, alkalies, etc.) and others brought by the blood and eliminated by the intestine (mercury, ricin, etc.) and the more indefinite chem ical substances which are found, under some circumstances, in the ingested food. (B) Bacteria play an important rOle in the causation of this disease. Booker's study of the summer diarrhceas of chil dren is most convincing in this respect. "No single micro-organism is found to be the specific exciter of the summer ' diarrhcca of infants, but the affection is generally to be attributed to the result of the activity of a number of varieties of bacteria, some of which belong to well-known species and are of ordinary occurrence and wide distribution, the most important being the streptococcus and proteus vulgaris." As to the mode of entrance into the mucosa, Booker says: "In the superficial epithelium of the intestine is apparently to be found the chief protcction of the mucosa against the invasion of bacteria. When the epithelium is preserved, bacteria are not found in the mucosa beneath, whereas they may be seen entering it in places where the epithelium has been lost or injured." Gartner's bacillus en teriditis is capable of provoking acute en teritis; and acute enterocolitis is asso ciated as a secondary affection, with a variety of specific infections (cholera, ty phoid fever, tuberculosis), intestinal dis eases, and other infectious processes (sepsis, influenza, pneumonia, scarlet fever, measles, diphtheria, etc.).
Seven cases of endemic dysentery in which a large aerobic bacillus was isolated. It developed well on ordinary culture-media, liquefying gelatin, curd ling milk, and producing gas. It is motile, somewhat like anthrax morpho logically, but is decolorized by Gram's method. Inoculated into animals, it produces a hwinorrhagic septicwinia with ulceration of the colon. Roger (Comp. Rend. de Biol., ser. xi, I, '99).