Many of the articles upon which horses feed are hard and dry. They require to be softened before they can be dissolved, or before they will part with their nutritive matter. One end of the horse's stomach seems designed for macerating these substances. It is lined by a membrane void of sensibility. All the food is first lodged in this macerating corner, from which, when sufficiently softened, it passes into the other extremity. Refractory matters are either de tained or returned till they are ready to undergo the digestive process.

Digestion consists in the extraction of the nutritious from the inert portion of the food. It is not a simple process, nor is it all conducted in the same place. It begins in the stomach and terminates in the bowels, probably at a considerable distance from the point at which the residue is evacuated. The stomach of the horse is very small. There must be some reason why it is so, but none has ever been discovered.* [In the horse's stomach digestion is very rapid. Hence a small stomach only is necessary. If it were large, it would dimin ish the size of the lungs. But large lungs are necessary for rapid and continuous action. Hence the necessity of a small stomach. But food in sufficient quantity is necessary, and thus the rapid digestion of the horse.]

* Inquiry seldom acknowledges defeat. A large stomach, it is said would interfere with the horse's speed. Perhaps it might. But it does not appear that the stomach was made small that he might be swift. Look at the pace of a camel and the size of his paunch.

It can not retain the food very long; the horse is almost constantly eating. At grass he eats as much in an hour, perhaps in half-an-hour, as would fully distend the stomach, yet he continues to eat for several hours in succession. The change, therefore, which the food undergoes in the stomach must be rapidly performed. The nature of this change is not precisely known. It is supposed that the gastric juice - that is, a juice or secretion furnished by the stomach - seizes the nutritive matter of the food, and combines with it to form a white milk-like fluid termed chyme. This, accompanied by the food, from which it has been extracted, enters the intestines, and there another change of composition takes place. Juices from the liver, from peculiar glands, and from the intestines itself, are added, and the whole combine to form a compound fluid termed chyle. This adheres to the inner surface of the bowels, from which it is removed by an infinite number of tubes, whose mouths are inconceivably minute, to the eye invisible. These little tubes or pipes, are termed lacteals or absorbents; they converge and run toward the spine, where their contents are received by a tube which empties itself into the left jugular vein.

Accompanied by the blood, the chyle proceeds to the lungs, passes through them, and becomes blood. Having undergone sanguification, this chyle, the product of digestion, is as much a constituent of the living animal as any other part of him.

It is not necessary to trace the food farther. Its nutritive matter having been extracted, and animalized by combination with animal juices, the product is removed as the mass travels through the intestines. By the time it has arrived at the point of evacuation, the food has lost all or most of the nutritive matter, and the residue is ejected as useless.

The nutritive matter is carried from the intestines to the blood-vessels, where it is mingled with their contents. To follow it further would be to trace the conversion of the Wood into the solids and fluids of which the body is composed In this work such an inquiry is not necessary.