THE ABDOMEN. 145 



capillaries, an active part being taken by the cells. By 

 the time they reach the liver the peptones have been 

 changed back into proteins. In fact, peptones seem to 

 have some poisonous effect upon the blood if they get 

 into it as such. 



The Large Intestine. The large intestine differs from 

 the small in size and in fixity of position, lying curved in 

 horseshoe shape above and around the small intestine. 

 It is five or six feet long, large in caliber, and is thrown 

 into crosswise folds. It has the same four coats as the 

 small intestine, but the mucous coat is pale and smooth, 

 without villi. Its glands are the crypts of Lieberkiihn 

 and the solitary glands. The arteries are branches of the 

 superior and inferior mesenteric and the nerves come 

 from sympathetic plexuses. 



The blind sac lying in the right iliac fossa, with which 

 the large intestine begins, is called the cecum, and into 

 this the ileum opens, the ileo-cecal valve preventing 

 regurgitation. Just below the ileo-cecal opening is the 

 vermiform appendix, a narrow, worm-like tube with a 

 blind end, varying in length from one to nine inches, but 

 generally about four and one-half inches long, which, so 

 far as is known, is functionless as well as dangerous. 

 People have been born without an appendix and it has 

 in rare instances grown again after operation. Its base 

 is located in the living by McBurney's point, a point two 

 inches from the anterior superior spine of the ilium on 

 a line drawn from the spine to the umbilicus. 



From the cecum the intestine ascends in what is known 

 as the ascending colon along the abdominal wall at the 

 right to the under surface of the liver, where it turns 

 in the hepatic flexure abruptly across the body to the 

 left, passing below the liver, stomach, and spleen in 

 the transverse colon. In the splenic flexure it turns down 

 the left abdominal wall, the descending colon passing to 

 the crest of the ilium, where there is another curve, 

 the sigmoid flexure, leading to the rectum, which passes 

 for six or eight inches down along the vertebrae, a little 

 10 



