GLANDS OF THE ORAL CAVITY. 



457 



excretory duct. The lobes, of which in the simplest glands (Fig. 178), 

 only a few (4-8) exist, are in their Fig. ITS. 



circumference generally elonga- 

 ted, pyriform, or rounded, not rare- 

 ly flattened, 0-5-0-72 of a line 

 long, 0-2-0-48 of a line broad, and 

 are each seated upon a branch 0-03- 

 0*05 of a line thick, of the excre- 

 tory duct, which measures 0*12- 

 0'3, or even 0-5 of a line (in the 

 glands of the root of the tongue). 

 They consist of a number of coiled 

 canals, presenting numerous simple 

 or compound, vesicular diverticula 

 (Fig. 179), and appear to be the 

 immediate continuations of the ex- 

 cretory ducts of the lobes, which, 

 as soon as they have entered the 

 latter, usually without diminishing 



in diameter, breakup successively into a certain number of them. What 

 have been called the glandular vesicles or acini, are nothing more than 



the dilatations and terminations of these canals, or ultimate branches of 

 the excretory ducts. Examined superficially, and under low magnifying 

 powers, they all appear uniformly rounded or pyriform; the exact ana- 

 lysis of a whole lobe, or still better of a dissected and injected gland, 

 shows, however, that their form is very various, rounded, pyriforra, or 

 elongated. It is impossible to describe at length all the forms which 

 they assume ; I will therefore only remark, that the ends of the glandu- 

 lar lobes frequently repeat, on a small scale, the figure and structure of 

 the seminal vesicles, and refer to the subjoined diagrammatic figure. 



FIG. 178. Racemose mucous gland from the floor of the oral cavity : a, investment of 

 connective tissue ; 6, excretory duct ; c, glandular vesicles ; rf, ducts of the lobes ; from Man. 

 Magnified 50 diameters. 



FIG. 179. Diagram of two ducts of a lobe of a mucous gland: a, excretory duct of the 

 lobe; 6, secondary branch; c, the glandular vesicles upon it in situ; d, the same separated 

 and the duct unfolded. 



