A. ORAL CAVITY, BY E. KLEIN. 509 



mucosa, besides numerous extremely thin- walled bloodvessels, 

 there are numerous lymph channels, both in the form of larger 

 lymphatic lacunae and of lymphatic vessels. The larger nerve 

 trunks lying externally to the first rows of glands, the num- 

 ber of which is much more considerable at the anterior than 

 at the posterior surface, give off fine branches, which run both 

 internally into the submucous tissue as well as externally into 

 the mucosa, where they may be followed in the former instance 

 between the glands and the muscles, in the latter as far as the 

 epithelium. 



The thickness of the mucosa is variable, and depends on the 

 size and number of the glands. In general the thickness of 

 the mucous membrane increases from the commencement of the 

 hard palate towards the point of the uvula, and it is always 

 somewhat thicker on the upper surface than on the lower. 



The acinous mucous glands of the soft palate are situated, as 

 has been noted above, in the submucous tissue. Their size 

 varies, and the largest are found in the uvula. Szontagh* 

 counted one hundred of them on the anterior surface of the 

 soft palate, forty on the posterior surface, and twelve on the 

 uvula. In the last-named situation they become larger, and 

 form in its upper half, or basis, a central layer, which, however, 

 is somewhat nearer to the anterior surface than to the posterior, 

 and is sometimes invested by the fasciculi of the azygos uvulae, 

 and at others is intercalated between the two muscles. 



The excretory ducts vary in their width, in the nature of 

 their coats, and in their direction. At the posterior surface of 

 the uvula in adults we find excretory ducts which become 

 wider near their orifice ; but the opposite obtains in the ducts 

 opening on the upper and lower surfaces of the soft palate. 

 The direction pursued by the excretory ducts is very rarely 

 rectilinear; the greater number, after they have received all 

 their tributary branches, run from the deepest part of the 

 mucosa perpendicularly towards the epithelium, then turn 

 off at an angle, and course obliquely towards the free surface 

 of the epithelium. They are for the most part lined with a 

 simple cylindrical epithelium ; in other instances, but less fre- 



* Loc. cit. 



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