As examples of the secretion of irritant matters from the blood may be mentioned almost all the different agents used as purgatives, and purgative agents accidentally taken in, these being as a rule absorbed and later secreted again on the intestinal surface, increasing the secretions in their passage:—also the morbid products of fevers which irritate the intestinal mucosa and glands as they are thrown out by them (rinderpest, lung plague, Southern cattle fever):—the purgative waters on certain “scouring lands” act in a similar way. Under the head of reflex action may be named the chills from exposure to cold rains, night dews, damp stalls or beds, and damp, hot buildings, seasons and localities. Under the head of nervous causes must be included strong emotions as excitement, fear, etc., which lead to increase of both secretion and peristalsis. Some horses are very subject to this and are known as “washy”. These have usually a slim abdomen and long loin, and scour whenever they are put to hard work. Other nervous animals with good conformation, but which fret under saddle or in harness will scour under specially severe work or under excitement. This is especially common in young colts while being “broken”, and will occasionally show in mares which are in _heat_. Cattle that have been on a specially succulent diet (turnips, beets, ensilage, grass) are liable to scour profusely if driven far or fast, and stock men seek to obviate this by feeding some dry bran, meal, and above all fresh dry brewer’s grains just before starting. Cows running at large when in heat are very liable to scour. An exclusive diet of turnips or beets will keep cattle in a chronic condition of mild diarrhœa, though not enough to interfere with rapid improvement in flesh. Chronic diseases of the liver by obstructing the flow of blood through the portal vein, cause intestinal congestion and predispose to diarrhœa. Of the various domestic animals horses are the most liable to superpurgation, from an undue dose of aloes acting on the very large colon and cæcum. Hence the importance of using such an agent carefully in the young, fat or debilitated especially, of the avoidance of cold drinks or exercise to excess after the aloes has been given, and of keeping from work during its operation or immediately after. _Symptoms._ These are of all degrees of severity from the frequent pulpy evacuations of animals fed exclusively on roots, (beets, turnips, potatoes), to the excessive and almost constant discharge of a dark colored liquid mingled with more or less mucus. The discharge may be of a light color and fœtid, indicating deficiency of bile, or of a dark yellowish brown and odorless.