_Causes._ The abomasum in the adult is protected against disorder, by the normal activity of the first three stomachs, macerating the food, presiding over the second and more perfect mastication, grinding it between the omasal folds into a firmly attenuated pulp and delaying its progress so that it arrives at the fourth stomach at short intervals and in small quantities only at a time. It follows that this organ is rarely involved in serious disorder unless as the result of the ingestion of poisons, or of excess of water, or from the presence of parasites. In the very young ruminant, however, the condition is reversed, the first three stomachs are as yet undeveloped, and incapable of receiving more than the smallest quantity of food or of retaining the same, and the abomasum alone is functionally active and receives at once practically everything that may be swallowed. In the first few weeks of life therefore the ruminant is exposed to almost the same dangers, from overloading, indigestion, inflammation and poisoning as is the monogastric animal. For the time, indeed, the undeveloped ruminant is in its physiological and pathological relations, a monogastric animal. For this early life therefore whatever applies to the soliped applies equally well to the ruminant. When allowed to suck at will from a healthy nurse, which completed its gestation about the time the young animal was born, indigestion is rare. But whatever interferes with the normal supply is liable to cause derangement. The withholding of the first milk—colostrum—the laxative properties of which are essential to clear away the intestinal accumulations of fœtal life—meconium; the placing of new-born offspring on the milk of nurses that bore their young many months before; bringing up of foals on cow’s milk; working, overdriving, hunting, shipping by rail, or otherwise exciting the dams; allowing too long intervals between the meals—feeding morning and night only, or morning, noon and night, the nurse being kept at work or pasture in the interval; feeding unwholesome food to the nurse; bringing up by hand, on cold and even soured milk, or that which has become contaminated by putrid leavings in the unscalded buckets. Some of these causes should be emphasized, for example the milk of excitement and fever, milk that is soured or putrid, and milk suddenly swallowed in excess. The nurse which is fevered or subjected to over-exertion has produced an excess of tissue waste and leucomaines which largely escape from the system in the milk. This milk is therefore at times unwholesome and even poisonous. Mares subjected to severe work or that fret much under lighter work, cows carried by car or boat, or driven violently, and any nursing animal which has been thrown into a fever from any cause whatever, is liable to yield toxic milk. This would include the milk of all severe diseases, as being liable to become charged with toxins and ptomaines and thus poison the young