PATCHES OF PEYER. 



459 



the crypts of Lieberkiihn, solitary glands, and Payer's and Brunner's 

 glands. 



The crypts of Lieberkiihn (fig. 154, a) are minute simple tubes, similar 

 to those in the stomach, though not so closely aggregated, which exist 

 throughout the small intestine. They open on the surface of the mucous 

 membrane by small orifices between the villi, and around the larger 

 glands ; but closed at the opposite end, they project into the submucous 

 layer, and are seldom branched. Their length is from ^th to ^th of an 

 inch: they are filled with a translucent fluid containing granules, and are 

 lined by a columnar epithelium. 



The so-called solitary glands (fig. 153, B ) are roundish white eminences, 

 about the size of mustard seed if distended, which are scattered along the 

 small intestine, but in greatest numbers in the ileum. Placed on all parts 

 of the intestine, and even on or between the valvular conniventes ; they 

 are covered by the vjlli of the mucous membrane, and are surrounded at 



Fig. 152. 



B 



A. PATCH OF PETER'S GLANDS FOUR TIMES EN- 

 LAROKD. 



a. Surface of the mucous membrane covered 



with villi. 



b. Pits over the follicles where the villi are ab- 



sent. 



B. MAGNIFIED REPRESENTATION OF AN INJEC- 

 TION IN THE RABBIT, BY FRET, OF THE 

 VESSELS SURROUNDIXH AND PENKTRATINU 

 TH B FOLLICLES IN A PATCH OF PETER (K61- 

 licker). 



the'r circumference by apertures of the crypts of Lieberkiihn. They are 

 closed lymph follicles beneath the mucous coat, which project into the 

 gut; and they are formed of a network of reticular connective tissue with 

 lymph-corpuscles between the meshes. Fine capillary vessels permeate 

 the mass; and it is surrounded by a plexus of lymphatic vessels. 



The glands of Pei/er (fig. 153, A ) (glandulae agminatae) exist chiefly in 

 the ileum, in the form of oval patches, which measure from half an inch 

 to two inches or more in length, and about half an inch in width. They 

 are situate on the part of the intestine opposite to the attachment of the 

 mesentery, and their direction is longitudinal in the gut: usually they are 

 from twenty to thirty in number. In the lower part of the ileum they are 

 largest and most numerous; but they decrease in number and size up- 



r. 



- 



a 



X 



