846 



THE INTESTINE. 



which they open by small orifices. They appear to be analogous to the 

 tubuli of the stomach, but they are placed farther apart from each other, and 

 are sometimes bulged inferiorly, but are hardly ever divided. Similar 

 tubules also occupy the whole mucous membrane of the large intestine. 

 The crypts of Lieberkiihn vary in length from the ^th to the /^th of a 

 line, and their diameter is about ^th of a line. The walls of the tubes are 

 thin, and lined with a columnar epithelium : their contents are fluid and 

 transparent, with granules interspersed, and they never contain fat. These 

 crypts are sometimes filled with a whitish substance, which most probably 

 consists chiefly of desquamated epithelium and mucus. 



The agminated glands, or glands of Peyer (who discovered and described 

 them in 1677), are found in groups or patches, having an oblong figure, and 



Fig. 591 A. Fig. 591 A. PATCH OP PETER'S 



GLANDS IN THE ILEUM. 



This figure represents, some- 

 what diagraminatically, and of 

 the natural size, a patch, of 

 Peyer's glands from near the 

 middle of the ileum of a young 

 subject : in the lower half of the 

 figure the mucous membraneand 

 the glands have been removed by 

 dissection, showing the impres- 

 sion left by the patch of glands 

 by the condensation of the sub- 

 mucous tissue : the piece of 

 intestine having been opened 

 along its meseuteric border, 

 the blood-vessels are seen ad- 

 vancing from the separated 

 margins towards the centre. 



varying from half an inch 

 to two or even four inches 

 in length, and being about 

 half an inch, or rather 

 more, in width. These 

 patches are placed length- 

 ways in the intestine at that part of the tube most distant from the mesen- 

 tery ; and hence, to obtain the best view of them, the bowel should be 

 opened by an incision along its attached border. 



The patches of Peyer's glands consist of groups of small, round, flattened 

 vesicles or capsules composed of a tolerably thick and firm wall of connective 

 tissue, usually filled with a whitish or rather greyish semi-fluid matter, con- 

 sisting of round nucleated cells and free nuclei, and situated beneath the 

 mucous membrane, the surface of which is depressed into little shallow pits, 

 at or rather under the bottom of which the capsules are placed. The inter- 

 mediate surface of the membrane is beset with villi and Lieberktihn's crypts : 

 the villi are also sometimes found even over the capsules, and the crypts are 

 collected in circles around the capsules, but do not communicate with them. 

 Opposite to the patches of Peyer's glands, the mucous and areolar coats of 

 the intestine adhere more closely together than elsewhere, so that in those 

 situations it is impossible to inflate the areolar coat. Fine blood-vessels are 

 distributed abundantly on the walls of the capsules, and give off still finer 

 capillary branches, which, supported by a delicate network of connective 



