THE SMALL INTESTINE. 373 



oblique. The circular layer is the principal plane of 

 fibres ; the longitudinal are most abundant near the curv- 

 atures ; the oblique fibres are scattered, although disposed 

 in a layer over the cardiac end. 



The cellular coat is formed of loose cellular tissue, 

 which connects the muscular and mucous coats. The 

 mucous lining of the stomach is thick, smooth, pale pink 

 in color, and, when the stomach is collapsed, thrown into 

 numerous longitudinal wrinkles, the rugae. The mu- 

 cous membrane presents under the microscope a honey- 

 comb arrangement of shallow, pit-like depressions, 

 about -%$-$ inch in diameter. At the bottom of these 

 alveoli the peptic and mucous follicles open. They 

 are both simple follicles, lined by columnar epithelium ; 

 in the peptic glands numerous spheroidal cells are 

 imbedded among the columnar epithelium ; these are 

 active agents in the elaboration of the gastric juice. The 

 mucous crypts are very abundant about the pylorus. 

 The free surface of the stomach is lined by columnar 

 epithelium. 



THE SMALL INTESTINE. 



The small intestine is a musculo-membranous tube, 

 about twenty feet long. It is divided into three parts, 

 the duodenum, jejunum, and ileum. The duodenum is 

 about ten inches long ; its diameter is greater than any 

 other part of the small intestine ; it is comparatively 

 fixed in position by the peritoneum ; it curves around 

 the head of the pancreas, and at first ascends, then 

 descends, and then runs transversely across the front of 

 the spine. The ascending portion is about two inches 

 long, invested by the layers of the lesser omentum ; it is 

 commonly found stained with bile ; the descending por- 

 tion, about three inches long, passes down in front of the 

 right kidney ; it receives the common bile and pancreatic 



