500 SPECIAL HISTOLOGY. 



that of the oral cavity ; above them, on the other hand, that is, on the 

 posterior surface of the soft palate from its free edge, upon the upper 

 surface of the uvula, in the region of the choance and Eustachian tubes, 

 and upon the vault of the pharynx, there is a ciliated epithelium like 

 that in the nasal cavity and larynx, to the description of which, below, 

 the reader may be referred. In this upper or respiratory section, the 

 mucous membrane is also redder, thicker, and more glandular than in 

 the lower division, otherwise, however, its structure is pretty much the 

 same, with the exception that it presents no papillae, which, however, in 

 some parts of the lower division are very little developed and rare, and 

 would even appear to be entirely wanting. Compared with that of the 

 oral cavity I find the mucous membrane of the pharynx to possess much 

 more and much stronger elastic tissue, which, in the deeper layers, forms 

 connected, very dense, elastic membranes. 



The pharynx contains two sorts of glands ; 1, racemose mucous glands 

 (vide supra, 134), and, 2, follicular glands. The former ^1 line in 

 diameter, have distinct apertures and abound more particularly in the 

 upper portions of the pharynx, where they form a perfectly continuous 

 layer on the posterior wall, in the neighborhood of the pharyngeal open- 

 ing of the Eustachian tubes, and upon the posterior surface of the velum, 

 diminishing in number lower down, follicular glands, simple as well as 

 compound, analogous to the tonsils, are met with in the vault of the 

 pharynx, where the mucous membrane is closely attached to the base of 

 the skull. Here a glandular mass, stretching from one Eustachian open- 

 ing to the other, and from one to four lines thick, may constantly be met 

 with ; it is, upon the whole, smaller, but otherwise its structure resem- 

 bles, in all essential respects, that of the tonsils ( 135). Besides this 

 mass, whose largest sacculations are situated in the middle of the roof 

 of the pharynx, and in the recesses behind the Eustachian apertures, 

 and which, in aged persons, frequently present enlarged cavities, filled 

 with puriform masses, there occur round the apertures of the tubes, 

 and upon them, towards the choance, on the posterior surface of the 

 velum palati, and on the lateral walls of the pharynx, as far as the 

 level of the epiglottis, more or less numerous, smaller and larger fol- 

 licles, whose size is too great for apertures of the mucous glands, and 

 which have in all probability the same structure as the simple follicles 

 of the root of the tongue, and receive the excretory ducts of the mucous 

 glands. 



The mucous membrane of the pharynx is rich in bloodvessels and 

 lymphatics. The former constitute superficially a network with elon- 

 gated meshes, sending short loops into the rudimentary papillae. The 

 nerves are very numerous, form superficial and deep plexuses, the former 

 with fine fibres of 0'001-'0015 of a line, which occasionally divide, and 

 whose ultimate terminations escape the eye. 



