184 ANATOMY FOB, NUKSES. [CHAP. XV. 



coat below. Besides these projections formed for absorption, 

 the mucous membrane is thickly studded with secretory glands ; 

 the larger number of these, found all over the surface of the 

 intestine, are called the glands or crypts of Lieberkuhn. These 

 glands are supposed to secrete the intestinal juice, succus en- 

 tericus. 



Again, in the corium of the mucous coat the lymphoid tissue 

 is collected into numerous solitary glands or follicles, and into 

 groups of glands, the Peyer's patches, the functions of which 

 are not yet clearly understood. 



The large intestine. The large intestine is about five feet 

 (1.5 metres) long, and from two and a 

 half to one and a half inches (63 to 38 

 mm.) wide; it extends from the ileum 

 to the anus. It is divided into the 

 caecum, with the vermiform appendix, 

 the colon, and the rectum. 



The ccecum (ccecus, blind) is a large 

 blind pouch at the commencement of 

 the large intestine. The small intes- 

 tine opens into the side wall of the 

 large intestine about two and a half 

 inches (63 mm.) above its the large 

 intestine's commencement, the caecum 

 forming a cul-de-sac below the opening. 



FlG. 117. CAECUM, SHOW- Aj i 1 , ,1 i i c ,1 



ING ITS APPENDIX ENTRANCE Attached, to the lower end or the caecum 

 OF ILEUM, AND ILEO-C.ECAL i s a narrow, worm-like tube about the 



VALVE. 1, caecum; 2, com- . > i 



mencement of colon; 3, en- size or a lead pencil, the vermiiorm 

 trance of ileum into the large ap pendix. The ceecum and appendix 



intestine ; 4, ileo-csecal valve ; f L ^ 



6, aperture of vermiform ap- lie just beneath the abdominal wall in 



pendix; 7, vermiform appen. 



The opening from the ileum into the large intestine is provided 

 with two large projecting lips of mucous membrane which allow 

 the passage of material into the large intestine, but effectually 

 prevent the passage of material in the opposite direction. These 

 mucous folds form what is known as the ileo-csecal valve. 



The colon may be subdivided into the ascending, transverse, 

 and descending colon, and the sigmoid flexure. The ascending 

 portion runs up on the right side of the abdomen until it reaches 

 the liver, then bends abruptly to the left, and is continued 



