Causes: Debility, age, anæmia, leucæmia, lymph gland, kidney, heart or lung disease, parasitism, dental or salivary disease, coarse, fibrous food, spoiled food, putrid water, gastric neoplasms. Symptoms: Impaired appetite, eating lime or earth, weariness, costiveness, coated dung, tympanies, diarrhœas, fatigue, sweating, unthrifty hide, pallid mucosæ, emaciation, colics. Lesions: Thickened right gastric mucosa, discoloration, mucus, petechiæ, opaque granular epithelium, gastric dilatation. Treatment: Remove causes, diet, watering, exercise, sunshine, bismuth, pepsin, acids, bitters, electricity, antiseptics, stomachics. _Causes._ These are in the main the causes which operate in producing the acute affection. In most chronic cases they act continuously on a system rendered susceptible by debility or otherwise. Among predisposing causes may be named: The debility of old age, anæmia, leucæmia, chronic diseases of the lymph glands, of the liver, kidney, heart, or lung, parasitic diseases, diseases of the jaws, teeth, or salivary glands which interfere with proper mastication and insalivation. Among exciting causes may be named: A coarse, fibrous, innutritious diet, a too bulky diet, spoiled fodders of all kinds, putrid drinking water, and stomach parasites (spiroptera, œstrus larva). Actual disease of the stomach—papilloma, cancer, actinomycosis, tumors, and oat-hair or other concretions are further causes. _Symptoms._ Impaired or capricious appetite, a disposition to lick the walls or earth, or to drink impure water, yawning, constipation with glossy mucus-covered fæces, and slight tympany, alternating with diarrhœa, small, accelerated pulse, susceptibility to perspiration and fatigue on slight exertion, unthrifty skin and hair, hide-bound, dry, hot mouth, coated tongue, pallor of the mucous membranes, loss of condition, and increasing weakness. Slight colics may occur at intervals, and the sluggishness may deepen into stupor or vertigo. _Lesions._ The right sac is usually the seat of more or less hypertrophy of the mucosa, which is thickened, rugose, with patches of dark red, gray and slate color, and covered with a layer of tenacious mucus. The surface may show warty-like elevations, or papillary projections, with here and there patches of blood extravasation. The epithelial cells are increased, opaque and contain many fatty granules. Dilatation of the stomach is not uncommon especially in old horses, and then the mucosa may be attenuated and smooth. Hyperthermia may be present, but is so slight that inflammation cannot be predicated from it and it is difficult to establish a diagnosis from chronic dyspepsia.