If 'peritonitis'--inflammation--is neglected, or drastic purgatives are too often and too plentifully administered, a peculiar contraction of the muscular membrane of the intestine takes place, and one portion of the bowel is received within another--there is 'intussusception'. In most cases, a portion of the anterior intestine is received into that which is posterior to it. Few of us have opened a dog that had been labouring under this peculiar affection without being struck with the collapsed state of the canal in various parts, and in some much more than in others. Immediately posterior to this collapsed portion, it is widened to a considerable extent. The peristaltic motion of the intestine goes on, and the consequence is, that the constricted portion is received into that which is widened, the anterior portion is invaginated in the posterior: obstruction of the intestinal passage is the necessary consequence, and the animal dies, either from the general disturbance of the system which ensues, or the inflammation which is set up in the invaginated part. I will say nothing of medical treatment in this case; for I do not know the symptoms of intussusception, or how it is to be distinguished from acute inflammation of the bowels. Acute inflammation will not long exist without producing it; and, if its existence should be strongly suspected, the treatment would be the same as for inflammation. The domesticated dog, from the nature of his food, more than from any constitutional tendency, is liable to constipation. This should never be neglected. If two or three days should pass without an evacuation, the case should be taken in hand; otherwise inflammation will be very soon established. In order to procure an evacuation, the aloetic ball, with one or two grains of calomel, should be given. Beyond that, however, I should not dare to go; but, if the constipation continued, I should have recourse to the castor-oil mixture. I should previously examine and empty the rectum, and have frequent recourse to the enema-syringe; and I should continue both. It would be my object to evacuate the intestinal canal with as little increased action as possible. DIARRHOEA