DIGESTION. 93 



Glands of the Small Intestine. 



There are four kinds of glands in the mucous membrane of the 

 small intestine. They are: duodenal, or Brunner's; glands of 

 Lieberkiihn; solitary; and agminated glands, or Peyer's patches. 



Brunner's glands are small, raceniose glands situated in the sub- 

 mucous tissue of the duodenum. Toward the end of the duodenum 

 they gradually disappear. 



The glands of Lieberkiihn are the most numerous of all the 

 glands of the small intestine, and they exist from the pyloric end to 

 the ileo-caecal valve. They are placed in a vertical direction in the 

 thickness of the mucous membrane and open between the villi. They 

 are about 1 / 100 inch in length. They have thin walls lined with a 

 columnar epithelium. 



The solitary glands are found in all parts of the mucous mem- 

 brane of the small intestine. They are minute, whitish, oval or 

 rounded bodies scattered singly in the intestine. They are closed 

 vesicles, and are situated in the submucous tissue. They are lymph- 

 nodules composed of retiform tissue and lymphocytes. 



The agminated glands (Peyer's) are formed of solitary glands, 

 disposed in oval patches. Usually there are fifteen to thirty of these 

 patches, from one-half to two inches in length, and one-half inch in 

 breadth. The ileum is their usual habitat, and they are seated oppo- 

 site the attachment of the mesentery. In the neighborhood of the 

 ileo-cascal valve they are larger and more numerous. As the duo- 

 denum is approached they are smaller and fewer. In youth they are 

 distinct, less so in adult life, and in old age may disappear. They are 

 the seat of ulceration in typhoid fever. The arteries of the small 

 intestine are the superior mesenteric and pyloric. The lymphatics 

 are numerous. The nerves are given off by the solar plexus. Be- 

 neath the mucous coat in the areolar tissue of the small intestine are 

 Meissner's ganglia. Between the muscular coats the ganglia of Auer- 

 bach can be found. 



THE LARGE INTESTINE. 



This is a cylindrical tube differing from the small intestine in 

 having a greater capacity and a sacculated appearance. It is about 

 five feet in length and extends from the ileo-csecal valve to the anus. 

 It nearly encircles the abdomen in its course. Like the small intes- 

 tine, it is divided into three parts: the caecum, colon, and rectum. 

 The head of the colon, the caecum, is a wide, blind pouch, or cul-de- 



