2 66 DIGESTIVE ORGANS. [SECT. 1 28. 



and bears on its outer surface a large number of papillae, similar to 

 those of the skin, which being generally simple, occasionally also 

 bifid (even with several processes when hypertrophied) , and conical 

 or filiform in shape, are o-i8"' in length, 0-04'" in breadth, and are 

 disposed without regularity, and so closely to oue another, that 

 their bases are almost in contact. 



The submucous tissue is of different kinds. Upon the floor of 

 the cavity, on the anterior surface of the epiglottis, and, above all, 

 on the freuula of the lips and tongue, and the ligaments of the 

 larynx, it is thin and yielding ; and in these places, accordingly, 

 the mucous membrane is very moveable upon the parts beneath. 

 Where glands occur in the submucous tissue, it is more compact, 

 as upon the lips and cheeks, or even, in a manner, cpiite unyielding, 

 as at the root of the tongue and soft palate ; and, at the same time, 

 larger masses of fat make their appearance in it, particularly in 

 the latter places. The submucous tissue is very firm, dense, and 

 mostly whitish on the alveolar processes of the jaws, Avhere, along 

 with the proper mucous membrane and the periosteum, it repre- 

 sents, so to speak, only one mass, the gum; also upon the hard 

 palate, where the mucous membrane is connected with the bones, 

 by means of an unyielding, thick, fibrous layer, which also contains 

 glands in certain parts; lastly, it has a similar character upon the 

 tongue, wherever papilla? are situated. In the last-mentioned 

 situation, the mucous membrane is most intimately connected with 

 the muscles, many muscular fibres sending processes into it, which 

 terminate more especially in a white, firm, and thick tendinous 

 layer, lying immediately upon the upper longitudinal muscular 

 fibres, and called fascia lingua (Zaglas). 



With regard to the intimate structure of the mucous membrane 

 of the oral cavity, the connective tissue preponderates in the sub- 

 mucous tissue, whilst the proper mucous membrane contains every- 

 where very numerous, mostly fine, elastic elements. Towards the 

 epithelium, the meshwork of the connective fibres is most dense, 

 and finally passes into a more structureless layer, which is equally, 

 incapable as in the corium of being demonstrated as an inde- 

 pendent membrane. The mucous membrane also contains ordi- 

 nary fat-cells, which are found more especially in the submucous 

 layer, sometimes in clusters, sometimes more isolated. 



The vessels of the mucous membrane are extremely numerous, 

 and present essentially the same characters as in the skin. The 

 smaller papillce contain only a single capillary loop, whilst in the 

 larger, simple, or branched ones there is a network of capillaries 



