SECT. 1 33-] ORAL MUCOUS GLANDS. 28 1 



injected and teased out, it is seen that their form is very various, 



Fie. 116. 



Diagram of two duets of a lobule of a mucous gland, a. Excretory duct of the lobule ; 

 b. lateral branch; c. the acini Of that branch in situ; d. the same spread out, and the 

 duct displayed. 



roundish, pyriform, or elongated. It is impossible to describe in 

 detail all the forms which are met with, and I will, therefore, only 

 further remark, that in point of appearance and structure, the 

 terminations of the lobules are, for the most part, copies, as it 

 were, on a small scale, of the seminal vesicles, as is represented in 

 the annexed figure, which is, however, partly diagrammatical. 



Fig. 117. 



All the finest gland-ducts and 

 vesicles, whose diameter varies 

 from o - o2'" to 008'", consist of a 

 special structureless envelope, the 

 membrana propria, of 0000 8" to 

 o - ooi2'" in thickness, and of a 

 simple epithelium of polygonal cells 

 (fig. 124), which very readily falls 

 oft', and then fills the acini in the 

 form of a granular mass. The epi- 

 thelial cells contain fluid mucus, 

 which is coagulated by acetic acid 

 (whence the cells become dark on 

 the addition of that re-agent), and a certain number of fat and 

 pigment-granules. 



The excretory ducts of the lobules, which, in the interior, are 

 traversed by connective tissue as well as enveloped by it, possess an 

 investment of connective tissue, with networks of fine elastic 

 fibres, and a simple layer, o-oo8"' to o'Ol'" thick, of cylindrical 

 cells. In the principal excretory ducts, the wall of the smallest 

 glands, which are very rich in elastic tissue, measures o"02 w ; that 

 of the larger, up to 0-03'" and 0-04'"; while the epithelium is o'oi'" 

 to o'oi 2'" in thickness. The glands are furnished with numerous 



Two acini of a racemose mucous gland, 

 of man ; magnified 300 times, a. Mem- 

 brana propria ; 6. epithelium, as it ap- 

 pears in the apparent section of a vesicle ; 

 c. the same seen from the surface. 



