STRUCTURE OF THE INTESTINE 



149 



glands is mainly composed of lymphoid tissue, which is aggregated at 

 intervals into more solid nodules (rig. 181) constituting when they occur 

 singly the so-called solitary glands of the intestine, and when aggregated 



FIG. 180. CROSS-SECTION OF A SMALL FRAGMENT OF THE MUCOUS MEMBRANE 

 OF THE INTESTINE, INCLUDING ONE ENTIRE CRYPT OF LlEBERKUHN AND 

 PARTS OF THREE OTHERS. (Magnified 400 diameters.) 



a, cavity of the tubular glands or crypts ; b, one of the lining epithelial cells ; c, the iuter- 



glandular tissue ; d, lymph-cells. 





FIG. 181. SECTION OF THE ILEUM THROUGH A LYMPHOID NODULE. (Cadiat.) 



a, middle of the nodule with the lymphoid tissue partly fallen away from the section ; 

 b, epithelium of the intestine ; c, villi : their epithelium is partly broken away ; d, crypts 

 of Lieberkiihn. 



together form the agminated glands or patches of Peyer. The latter 

 occur chiefly in the ileum. 



The villi with which the whole of the inner surface of the small 



