THE STOMACH.--This organ is very small in the horse in comparison with that of the ox. It holds only about four gallons, and is situated just back of the curtain which separates it from the lungs. It lies mostly to the left side. The walls of the stomach being composed of three coats. That on the outside is called the serous membrane, a name applied to membranes which line closed cavities, such as the abdominal cavity. The inside lining is a continuation of the mucous membrane lining the organs before mentioned. The lining in the left part of the stomach or the part where the food is prepared for digestion is the same color as that of the mouth. The lining of the right part of the stomach, which is the true digestive part, is of a deep red color resembling velvet, and when placed under a microscope has the appearance of a honey-comb. When the stomach is empty this membrane is thrown into loose folds. Several small openings may be noticed through which the gastric juice and pepsin from the glands, situated in the walls of the stomach, enters. These are very important fluids as they assist greatly in digesting the food. The third coat is known as the muscular coat already mentioned. Its action is to give the stomach a churning motion, rolling the food around and mixing it with the juices. The opening to the stomach is guarded by a valve which prevents the food from passing back through the gullet. There is also a valve at the opening of the bowels, preventing any coarse, undigested food from entering them. The stomach is held in its place by five large ligaments, and is well supplied by blood-vessels and nerves. Digestion of the food takes place very quickly in the horse in comparison to other animals. Frequently a change of food or working too soon after eating will interfere with the digestion, thus setting up what is known as indigestion. This is a very painful disease in the horse. After the food is acted upon by the juices in the stomach it changes into what is known as chyme, which passes into the bowels. THE BOWELS.--They are divided into two parts--the large and small.