THE ALIMENTARY CANAL. 115 



The sub-mucosa consists chiefly of fibro-elastic bundles and pene- 

 trating blood-vessels and nerves. 



The muscular coat is in two layers, an inner circular and an outer 

 longitudinal, separated b} r connective tissue. 



The serous coat consists of connective tissue and endothelium. 



There are four varieties of glands which occur in the intestinal 

 wall. The glands of Lieberkuhn occur in the mucosa and are dis- 

 tributed along the whole course of the small and large intestine, 

 being found between the villi. They are simple tubular depressions 

 provided with basement membranes and secreting cells. The 

 glands of Brunner are of the same type as the pyloric glands of the 

 stomach, but owing to repeated division they have more the appear- 

 ance of the compound sacular than of the tubular variety. They are 

 serous, and not of the mucous type. They occur in the duodenum. 

 The solitary glands are to be found in the sub-mucous coat and con- 

 sist of isolated lymph follicles. They occur in the small and large 

 intestines. Peyer's patches are compound glands of the racemose 

 variety. They occur in the mucosa and sub-mucosa. They should 

 be sought in the small intestine, more especially in the ileum. 

 Goblet cells are of frequent occurrence in the stomach and intestine. 

 The nerve supply of the alimentary tract is from the cranial and 

 sympathetic nerves. 



Laboratory exercise No. 35. Small intestine. Fix in corrosive sub- 

 limate, embed in celloidin, and stain with haematoxylin and eosin. Ex- 

 amine with L. P. and H. P., and demonstrate the following structures: 

 Columnar epithelium, goblet cells, membrana propria, villi, tunica 

 propria, capillaries, glands of Lieberkuhn, Brunner's glands, Peyer's 

 patches, solitary glands, muscularis mucosse, sub-mucosa, circular mus- 

 cle layer, longitudinal muscle layer, serous coat, and endothelium. An 

 injected specimen should be examined to demonstrate the capillary net- 

 work. Drawings. 



LARGE INTESTINE. 



The large intestine differs chiefly from the small intestine in 

 possessing thicker walls and fewer glands. It is supplied with soli- 

 tary follicles and the glands of Lieberkuhn, the latter containing 

 many goblet cells. There are the usual coats mucosa, sub-mucosa, 

 muscular coat, and serous coat. 



