_Causes._ The dog is susceptible because of its varied, irregular, stimulating, often excessive diet, and its close confinement and lack of wholesome outdoor exercise. The conditions which predispose to or excite gastritis tend equally to enteritis. Youth, canine distemper, over-exertion, an exclusive meat diet, and chills from plunging into cold water when exhausted with hunting are to be specially noted. Spoiled meats charged with the germs of infection, or with putrefactive bacteria and their toxic products are common causes. Then any old standing disease or other cause of general debility will predispose to the attacks of such otherwise harmless germs. The irritation caused by intestinal parasites is an occasional factor. _Lesions._ The mucosa is congested, ramified, spotted or dark and slaty; it together with the submucosa is swollen and infiltrated, and with points of ecchymosis, extravasation or even ulceration. The surface has a thick layer of mucopurulent matter. The solitary glands are swollen and charged with small lymphoid or pus cells and have a congested areola. The mesenteric glands are congested and the liver usually congested softened or mottled. In chronic cases there may be hyperplasia, polypi, cystoid degeneration of the follicles, etc. _Symptoms._ There may be dullness, drowsiness, a seeking of seclusion, inappetence, hyperthermia (102 to 104°), ardent thirst, arched back, abdominal rumbling, tympany or tucked up tender abdomen, and a very temporary constipation, early giving place to diarrhœa. If however the inflammation is confined to the rectum and floating colon, constipation may persist. There are intermittent colics, frequent lying down and rising, or rising on the hind limbs only and when the belly is handled the patient may whine. The mouth is sour, hot, clammy, and red, and the dorsum of the tongue furred. The nose is dry and burning, the eyes congested, sunken and watery. The fæces may be early soft or liquid and bilious, then as the defecations increase they pass through shades of gray to black or reddish black from the admixture of effused blood, and show bubbles and fœtor. Vomiting is usually an early symptom (septic matters in septic poisoning) and as the disease advances there is much fruitless straining and even protrusion of the congested and excoriated rectum. Icterus is common from infection of the gall ducts or the absorption of toxins into the portal vein. Weakness and debility amounting even to paresis may appear in the end. In chronic cases there are emaciation and debility, unthrifty hair and skin, cutaneous eruptions, pallor of the mucosæ, fœtid breath, foul teeth and tongue, with irregular appetite, alternate constipation and diarrhœa, and, in case of implication of the duodenum and liver, icterus. The abdomen is retracted and tender.