XXIl] INTESTINE 175 



1, the cells with hyaline border, the goblet cells, the 

 basement membrane, the connective tissue network 

 with contained leucocytes, the capillaries a little below 

 the basement membrane (these will not be obvious, if 

 they are collapsed), the bundles of muscle-cells. In 

 some sections the central lymphatic space will be seen, 

 bounded by a sharp line probably showing one or more 

 nuclei of its constituent cells. 



3. Snip off a few villi from a fresh intestine, and tease in 

 salt solution. Note especially the hyaline border of the columnar 

 cells and its striation. 



4. Vertical transverse sections of the large in- 

 testine. Observe 



The longitudinal and circular muscular coats. 



The submucous coat and the muscularis mucosae 

 both more conspicuous than in the small intestine. 



The mucous membrane, probably thrown into longi- 

 tudinal ridges, the submucous tissue running up into 

 the ridges. 



The absence of villi. 



The intestinal glands (glands of Lieberkuhn) ; they 

 are broader than in the small intestine, and have more 

 connective tissue (chiefly retiform) between them. The 

 epithelium covering the free intestinal surface or the 

 ridges between the glands consists of long columnar 

 cells ; in the glands the cells are shorter. The cells have 

 usually a thin hyaline border. In some animals (e.g. 

 dog) there are many distinct mucous cells. 



5. Examine sections of a small intestine in which 

 the blood vessels have been injected, and note the 



