The manyplus abounds internally in a number of leaves, called laminæ. Some of these are attached to the upper and lower portion of the division, and also float loose, and penetrate into the oesophagian canal. The laminæ have numerous projections on their surface, resembling the papillæ to be found on the tongue. The action of this stomach is one of alternate contraction and expansion: it secretes, however, like the other compartments of the stomach, its due share of gastric fluids, with a view not only of softening its contents, but for the purpose of defending its own surface against friction. The mechanical action of the stomach is communicated to it partly by the motion of the diaphragm, and its own muscular arrangement. It will readily be perceived, that by this joint action the food is submitted to a sort of grinding process. Hence any over-distention of the viscera, from either food or gas, will embarrass and prevent the free and full play of this organ. The papillæ, or prominences, present a rough and sufficiently hard exterior to grind down the food, unless it shall have escaped the reticulum in too fibrous a form: foxgrass, cornstalks, and frosted turnips are very apt to make sad havoc in this and other parts of the stomach, owing to their unyielding nature; for the stomach, like other parts of the organization, suffers from over-exertion, and a corresponding debility ensues. The fourth division of the stomach of the ox is called _abomasum_. It somewhat resembles the duodenum of the horse in its function, it being the true digestive stomach. It is studded with numerous nerves, blood-vessels, and small glands. It is a laboratory admirably fitted up by the Divine Artist, and is capable of carrying on the chemico-vital process as long as the animal lives, provided its healthy functions are not impaired. The glands alluded to secrete from the blood a powerful solvent, called the _gastric juice_, which is the agent in reducing the food to chyme and chyle. This, however, is accomplished by the united agency of the bile and pancreatic juice. Both these fluids are conveyed into the abomasum by means of small tubes or canals. Secretions also take place from the inner membrane of the intestines, and, as the result of the united action of all these fluids, aided by the muscular motion just alluded to, which is also communicated to the intestines, a substance is formed called _chyle_, which is the most nutritious portion of the food, and has a milky appearance. The chyle is received into a set of very minute tubes, called _lacteals_, which are exceedingly numerous, and arise by open mouths from the inner surface of the abomasum and intestines. They receive the chyle; from thence it passes into a receptacle, and finally into the thoracic duct. The thoracic duct opens into a vein leading directly to the heart; so that whatever portion of the chyle is not actually needed by the organism is thoroughly mixed with the general mass of blood.