Tumors of different kinds have been found in the walls of these organs, though by no means frequently. Epithelial hypertrophy and papilloma have been found in the ox the former undergoing necrotic changes. Chondroma is reported by Kitt, Sarcoma by Cadeac and Beylot. There seems to have been a special tendency to invade the demicanal, and to interfere with deglutition, rumination, and the passage of food into the third stomach. The impairment and loss of appetite and of rumination, the presence of tympany, and the general loss of condition are suggestive. If the disease of the demicanal leads to antiperistaltic movements of the œsophagus which can be felt by the hands pressed on the jugular furrows the diagnosis may possibly be made. _Treatment_ is manifestly hopeless. To be effective it must be surgical and would too often entail excision of the affected part of the viscus and careful suture of its walls. This would be even more hopeless when the demicanal was the seat of disease. Temporary palliation might be secured by a sloppy diet, the withholding of all rough food which would demand rumination, and the use of common salt, saline laxatives and abundance of water. ANIMAL PARASITES OF THE RUMEN AND RETICULUM. Infusoria. Amphistomum Conicum. Actinomycosis. Tumors: Papilloma, Chondroma, Sarcoma. Treatment—palliation or surgical. Colin describes and figures as many as eight varieties of infusoria found habitually in the first two stomachs. All appear to be introduced with the food, in the infusions of which they also appear, and they find in the fermenting mass of ingesta in the first two stomachs a favorable medium in which to grow and multiply. It cannot be shown that they are in any way detrimental and they have even been supposed to be beneficial to digestion as glycogen has been demonstrated in their protoplasm. Like the bacterial ferments they doubtless assist in the disintegration of the mass of food. _Amphistomum Conicum._ This is a trematode worm about the size of an apple-seed (10 millimetres long by 2 millimetres thick), rounded at both ends, slightly curved on itself, and, as usually found, of a bright red color. It attaches itself by its sucker (on thick end), usually in the vicinity of the demicanal. Its life history is closely allied to that of the distomata, but as it is not known to prove at all injurious to its host, it possesses no pathological importance.