CUTANEOUS AND MUCOUS FOLLICLES. 



669 



[Fig. 277. 



A section of Ihe small Intestine containing 



in contact ; but in the adult, the intervals increase, so as to occupy more 

 space than the apertures. The glandulae of the small intestines have long 

 been known under the name of the follicles of Lieberkuhn ; they become 

 particularly evident (Fig. 275) when the mucous membrane is inflamed, being 

 then filled with an opaque whitish secre- 

 tion, which is absent in the healthy state. 

 Besides the foregoing descriptions of 

 solitary glandulae, the Ccecum and the 

 lower part of the Rectum contain a num- 

 ber of simple and large follicles, which 

 produce slight rounded elevations on the 

 surface of the mucous membrane ; the 

 centre of each of these elevations is per- 

 forated by an aperture of the follicle ; and 

 around this are seen the orifices of the 

 tubular coeca, which closely envelope 

 the globular follicle (Fig. 270). These 

 seem most abundant where the largest 

 quantity of mucus is required. They 

 have been confounded with the glands of 

 Brunner ; but are rather analogous to the 

 solitary Peyerian glands, presently to be 

 noticed. 



875. The true glands of Brunner are 



chiefly situated in the Duodenum ; and some of the s lands of Peyer ' as shown under 



they lie not in the mUCOUS but in the the 'P e - These glands appear to be 

 J . small lenticular excavations, containing, ac- 



sub-mucous tissue, where they form a cording lo Boehm , a white, milky and rather 



Continuous layer of white bodies SUr- thick fluid, with numerous round corpuscles of 

 rounding the whole intestine. Their various sizes, but mostly smaller than blood- 

 size, Unless diseased, is Scarcely that of S lobules - The meshes seen in the cut are the 



a hemp-seed ; each consists of nume- ordinary tripe-like folds of the mucous coat, 



V /. i , and not the venous texture spoken ot under the 



rous minute lobules, of which the ducts fo iii c i e s.] 

 open into a common excretory tube ; 



and in the lobules may be distinguished the minute ramifications of these 

 ducts, with clusters of follicles forming acini, of which about six hundred 

 are computed 'to exist in each. Hence these glands 

 are of complex structure, much resembling that of the 

 Salivary glands and Pancreas, and entirely differing 

 from all the other glandulse of the walls of the ali- 

 mentary canal. Of the peculiar nature of their secre- 

 tion nothing is known. 



876. The so called Peyerian glands constitute, 

 when aggregated together, large patches on the mucous 

 membrane of the small intestine, where they are 

 known as the glandulse agminatse ; and it is to 

 these alone that Peyer's name is usually applied. 

 Similar bodies, however, known as the glandulse 

 solitarise, exist separately in the lower part of the 



small intestines ; where they have been confounded with the glands of Brun- 

 ner, which do not extend beyond the commencement of the Jejunum. The 

 glands of Peyer, when examined in a healthy mucous membrane, present the 

 appearance of circular white slightly-raised spots, about a line in diameter, 

 over which the membrane is usually less set with villi, and very often entirely 

 free from them. Each of these white spots, of which a large number are 

 contained in the agminated glands, is surrounded by a zone of openings like 



278. 



Conglomerate gland of 

 Brunner, from commence- 

 ment of duodenum; mag- 

 nified a hundred limes. 



