y^ PRACTICAL MICROSCOPY. 



PRACTICAL DEMONSTRATION. 



The intestines of the dog or rabbit are more commonly used for 

 practical work, for reasons already alluded to. The tissue should be 

 cut in small pieces, and hardened quickly in alcohol. When human, 

 intestine can be obtained fresh, a piece, say three inches long, should 

 be emptied of its contents, filled with alcohol by tying the ends, and 

 the whole hardened in strong spirit. Under no circumstances should 

 the gut be washed, and great care must be taken to avoid injuring the 

 delicate cells covering the villi. Vertical sections with the micro- 

 tome are the most valuable. Stain with haema. and eosin, and mount 

 permanently in dammar. 



VERTICAL SECTION OF THE ILEUM, INCLUDING POR- 

 TION OF A PATCH OF PEYER. HUMAN. 



(Vide Fig. 68.) 

 OBSERVE: 



(L.) 



1. The villi. (a) That they are of varying lengths, slender, 

 wavy, and delicate, (b) The covering of columnar cells. (The 



FIG. 68. INTESTINAL Mucous MEMBRANE THROUGH A PEYER'S PATCH, VERTICAL SECTION. 

 Stained with Haema. and Eosin. X 250. 



A, A, A. Villi. 



B. Transverse sections of crypts of Lieberkiihn. 



C, C. Crypts in vertical section. 



D, D, D. Nodules of lymphoid tissue constituting a patch of Peyer. 



E. Muscularis mucos. 



F. Submucosa. 



