In man three distinct forms are recognized. 1. =Catarrhal dysentery=, with frequent small stools of rosy mucus, and blood; and later pus, scybala, passed with tenesmus, but no sloughs and little odor; 2. =Diphtheritic dysentery=, with thin watery bloody discharges having a pronounced cadaveric odor; also tenesmus, sloughs, and increasingly offensive smell; 3. =Amœbic dysentery= with frequent bloody mucus stools, tenesmus sloughs and fœtor, but with distinct remissions or intermissions. With the latter, amœbæ are found abundantly and more so in the more acute cases with alkaline stools. They are found in the fresh warm stools, 5 to 8 times the size of a red blood globule and oval, pyriform or irregular in form, with nucleus and nucleolus. Kartulis and Hlava succeeded in inducing dysentery in cats and dogs by injecting pure culture of the amœba, and the former testifies that dogs in Egypt take the disease spontaneously, and their stools contain the same amœba coli as is found in man. Cunningham who investigated the subject in India found amœba in the bowels of healthy men, and also abundantly in the fæces of horses and cows, which have naturally the requisite alkaline reaction. The mere presence of the amœba therefore may not be sufficient to cause the disease, but with the requisite predisposition and an alkaline condition of the intestinal contents, it is manifestly an important factor in the disease. The causative microbes in other forms of dysentery have not been identified, but under the requisite irritation and local debility one can easily conceive of the ordinary bacterial ferments of the intestine, concurring with others introduced from without, in determining the morbid condition. With better hygiene the disease is steadily diminishing in man and beast, though violent epizootics (in cattle) still appear in connection with wars (siege of Belfort, 1870, Zundel), and carriage by sea in hot climates (Mediterranean trade, Bouley).