•1 



SPECIAL HISTOLOGY. 



The vessels of the mucous membrane are very numerous, and 

 present essentially the same arrangement as in the skin. The 

 Firr 16 7 # smaller papilla contain only 



a single capillary loop, whilst 

 in the larger, either simple 

 or branched, a network of 

 capillaries may be observed 

 (fig. 167) ; this is especially 

 the case in the gums, the 

 palate, the glandular region 

 of the root of the tongue, the 

 lips, and the lower surface of 

 the tongue. The investigation 

 of the nerves presents many 

 difficulties. If caustic alka- 

 lies be added, a wide net- 

 work of the finer and finest 

 branches is rendered distinct in the outermost layers of the 

 mucous membrane, in which also, divisions of the nervous 

 fibrils may be observed in some localities, particularly upon 

 the anterior surface of the epiglottis ; on the other hand, it is 

 often impossible to detect so much as a trace of nerves in the 

 papilla. Sometimes, however, even in these, especially in the 

 larger, one or two, often twisted, nerve-fibrils of 002'" in dia- 

 meter, diminishing to 0001 2'" may be detected, without its being 

 possible to make out their ultimate destination ; upon the lip 

 the papilla possess axile-corpuscles similar to, but smaller than, 

 those of the hand, though not in all individuals. I found here, 

 also, the nerve-coils described by Gerber (see § 37). Of the 

 origin and relation, in the t. mucosa itself, of the abundant lym- 

 phatic vessels of the oral mucous membrane, nothing is known. 



§ 130. 



The epithelium of the cavity of the mouth (fig. 167), is a so- 

 called pavement epithelium, consisting of many superimposed 

 layers of roundish, polygonal, more or less flattened cells. 

 Taken altogether, this epithelium is a transparent, whitish, pel- 

 licle, 01 — §'%" thick on the average, very flexible, but possess- 



Fig. 167. A. simple papilla with manifold vessels and epithelium, from the gum of 

 a child, x 250. 



