=ACTION OF BARIUM ON DOMESTIC AND FARM ANIMALS.= Barium in the form of barium chlorid has been recently introduced into veterinary therapeutics by Dieckerhoff[237] in the treatment of constipation, but Winslow[238] says that "the doses required to produce catharsis in the horse are almost toxic," and he advises against the intravenous use of this remedy. Fröhner[239] has carefully summarized the literature on the use of barium chlorid in veterinary work, and reports that its use in the Zürich clinic has recently been so unsatisfactory that it is now seldom employed and that in the last ten years the preponderance of reports in the literature are unfavorable to the use of this agent in colic. After the administration per os, much of the barium must be carried off in the diarrheal stools. A number of deaths in horses have been attributed to the use of this agent. No doubt the presence of sulphates, etc., derived from the food would render the barium insoluble in the gastro-intestinal tract, and this would explain the lack of poisonous action in certain of the cases in which large doses of barium proved harmless. Husard and Biron administered daily doses of 8 grams of barium chlorid to one horse, and the same amount of barium carbonate to a second horse, for several days. A fortnight later the first horse unexpectedly died, and the second a few days later. The post-mortem examination was negative.[240] A third horse fed with barium carbonate also died suddenly. Recently barium occurring in brine has given rise to acute poisoning in stock.[241] In a case reported by Stietenroth[242] the horse died after the injection of 0.5 gram of barium chlorid into the jugular vein. A number of sudden deaths in horses after the intravenous injection of 0.7 gram and over of barium chlorid have been collected by Fröhner.[243] The lethal dose by mouth for acute poisoning with barium chlorid in horses lies between 8 to 12 grams, while cattle require much larger doses (40 grams)[244] to induce death. Dieckerhoff advises against the use of barium chlorid in the treatment of constipation in sheep. After a dose of 6 grams of barium chlorid a 2-year-old healthy ram appeared perfectly well, but the following day he was depressed, refused to eat, staggered, and became so weak that he was unable to stand. The muscles of the extremities were paralyzed and the animal died. "The post-mortem examination revealed oedema of the lungs, slight cloudiness of the heart muscles, numerous small hemorrhagic spots on the mucous membrane of the small intestine, and stagnation of the blood in the vessels of the small and large intestines. Similar symptoms and lesions were found in a lamb 4 months old which was given per os 6.0 grams of barium chlorid dissolved in 200 grams of distilled water."[245]