œsophagus to the rumen; there it remains for some time, subject to the action of heat, saliva, mucous and the secretion of the organ. The tougher the food the longer it is retained. From the rumen the food passes to the recticulum, where the operation of maceration, commenced in the first stomach, is continued, the operation being facilitated by a slow, churning movement characteristic of both organs. The recticulum also appears to be the special receptacle of the fluid that is swallowed, for this at once passes into it, without going into the first stomach. The precise nature of the action of the secretions is uncertain. It is supposed to be a fermentation; no doubt at all times a certain proportion of gas is evolved from the food, but excessive fermentation is indicative of disease (Hoove), and of rapid and dangerous chemical change in the contents of the rumen. The pulpy mass, to which the food has been reduced by the chemical change and churning movement of the first two digestive cavities, is now prepared for thorough mastication by the teeth, and for ultimate solution by the digestive fluids. This mastication is _rumination_, or “chewing the cud.” The return of the food to the mouth for this operation is effected by the churning movement and by the contraction of the diaphragm and abdominal muscles, which press upward against the rumen and recticulum. The act of regurgitation is very evident to an observer, who sees a large mass ascend from the paunch and distend the œsophagus with an eructating noise. At the moment that a mass of the food passes into the mouth, the accompanying liquid is swallowed into the first of the three stomachs, leaving the solid portion to be slowly ground by the teeth. The length of time thus taken varies with the toughness of the food. Young and very old animals take longer to chew the cud than healthy adults. When the food has been sufficiently comminuted it is again swallowed, some of it into the first two stomachs; but, by a peculiar mechanism of muscular contraction; the passage into the first is so closed that the greater portion of it passes through the opening into the third stomach, from which it goes into the abomasum. The function of the omasum appears to be to regulate the descent of food into the abomasum, though some means of assimilation may take place between its many plies. The last stomach, as already stated, completes the process of digestion. Loss of the Cud This is a mere symptom which accompanies many diseases, and even morbid conditions, which scarcely deserve the name of disease, and will yield with the removal of the ailment of which it is a mere symptom. Sometimes it may be present when nothing else is sufficiently tangible to warrant treatment, or it may continue after the disease otherwise seems to have been removed.