hi] the digestive organs 45 



There are two kinds of glands in the small intestine, the 

 so-called crypts of Lieberkiilm and Brumier's glands, but the 

 latter are restricted to the duodenum, not being found in the 

 ileum. The crypts are tubular depressions in the mucous mem- 

 brane, and occur also in the large intestine, being very niimerous 

 throughout the greater part of the intestinal canal. Brumier's 

 glands are situated in the submucous tissue of the duodenum and 

 communicate with the lumen by ducts which traverse the mucous 

 membrane. They are especially numerous in the horse. We 

 also find numerous patches of lymphoid tissue in the mucous 

 coat of the small intestine. These are similar to the tonsUs 

 which are two larger lymphoid masses at the entrance to the 

 pharynx. Those occurring in the small intestine are known as 

 Pe Jeer's patches. 



Lieberkiihn's and Brunner's glands secrete the succus 

 entericus or digestive juice of the small intestine. The ferments 

 present in this juice and their action on the different classes of 

 food are described in the second volume. 



The Liver. Communicating with the duodenum by the bile 

 duct is the liver which is the largest gland in the body. It is 

 composed of round, oval or polyhedral lobules consisting of the 

 liver cells among which ramify the branches of the bile duct and 

 numerous blood vessels and lymph vessels. The lobules are 

 separated by connective tissue, and in the pig this separation is 

 complete, but in man and many animals is incomplete; the 

 lobules however become more perfectly divided as a result of 

 certain diseases such as alcoholism in which case the liver in 

 man comes to resemble that of the pig. The blood supply of 

 the liver is peculiar, for besides receiving arterial blood from the 

 hepatic arteries it is provided with a large quantity of venous 

 blood which is brought to it by the portal vein from the stomach, 

 spleen and alimentary region. It is obvious, therefore, that a 

 great variety of metabolic products must be brought to the liver, 

 and correlated with this fact we find that the liver discharges 

 a number of important functions connected with the general 

 metabolism of the body. It stores up carbohydrate material in 

 the form of glj^cogen, releasing it into the blood as sugar, the 

 percentage of which is thereby kept constant; it makes urea 

 and uric acid which are discharged as waste products bj- the 

 kidneys ; and it manufactures bile which is poured out into the 

 small intestine and utilised there for digestive purposes. 



