SMALL INTESTINE 



161 



VERTICAL SECTION OF THE ILEUM, INCLUDING PORTION OF A 

 PATCH OF PEYER. HUMAN ( Vide Fig. 106) 



OBSERVE : 



(L.) 



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

 wavy and delicate. (&) The covering of columnar cells. (The 



FIG. 106. INTESTINAL Mucous MEMBRANE THROUGH A PEYER'S PATCH. VERTICAL 

 SECTION. STAINED WITH H^MATOXYLIN AND EOSIN (X250). 



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 mucosae. 



F. Submucosa. 



free extremities of many of the villi in the drawing are seen 

 broken, and the epithelium is wanting in places. It is almost 

 impossible to secure perfect villi from human intestine, on account 

 of the length of time usually intervening between death and the 

 removal of the tissue.) (c) Oblique sections. 



2. The crypts of Lieberkiihn. 



3. The lymphatic nodules (so-called solitary glands), consti- 

 tuting the elements of a patch of Peyer. (a) Their projection 

 upon the mucous surface of the gut between the villi. (&) 

 The covering with epithelium on their free borders. (They are 



K 



