460 



SPECIAL HISTOLOGY. 



Fig. 181. 



present a whitish color, and closely resemble the capsules of Peyer's 

 patches, the solitary glands, the vesicles of the spleen and of the 



lymphatic glands. They con- 

 sist of a tolerably solid coat, 

 about 0-002--003 of a line 

 thick, composed of more ho- 

 mogeneous connective tissue, 

 without elastic fibres, and 

 of grayish white contents, 

 which, when the follicle is 

 pricked, exude in the form of 

 a drop, which becomes diffused 

 through water, and consists of a fluid with formed particles. The former, 

 alkaline in its reaction, is present in excessively small quantity, so that 

 it appears to be merely the connecting medium of the latter, which 

 consist of cells of 0-003-0-005 and free nuclei of 0-002-0-0025 of a 

 line without any determinate character. Acetic acid renders the cells 

 granular, and thence communicates a whitish tinge to the contents ; but 

 it precipitates no mucus, the fluid differing decidedly in this respect from 

 the ordinary mucous secretion and agreeing with that of the splenic cor- 

 puscles. The position of the follicles is usually such, that they form a 

 connected, almost simple layer, between the external coat and the epi- 

 thelium of the follicular glands, yet there are localities, at least in ani- 

 mals, where two follicles are found behind one another, or at greater 

 intervals. 



The vessels of the follicular glands are very numerous, and may often 

 be traced naturally injected, in man. Small arteries enter from without, 

 passing through the fibrous coat to the interior, ramify between the folli- 

 cles, as they ascend, in an elegant arborescent manner, and terminate 

 in the papillae and on the follicles. The vessels of the former present 

 the same relations as those of the other simple papillae, and are either 

 simple or complex loops ; around the follicles they form an exceedingly 

 elegant and abundant network, whose finest vessels, 0'004-0*006 of a 

 line in diameter, take a wavy course, forming a moderately close net- 

 work immediately upon the membrane of the follicle. The efferent 

 veins converge from these two localities, and are wide and numerous. 

 Lymphatic vessels also, according to E. H. Weber (Meckel's Archiv, 

 1827, p. 282), appear to proceed from these glands, and I have myself 

 noticed nerves upon them. 



The tonsils are, according to my investigations, nothing but an aggre- 



FlG. 181. Follicular gland from the root of the tongue in Man : a, epithelium lining it ; b, 

 papillae 5 c, external surface of the follicular gland, with the coat of connective tissue ; e, 

 cavity of the gland ; /, epithelium ; g, follicle in the thick wall of the gland. Magnified 30 

 diameters. 



