GLANDS OF THE ORAL CAVITY. 



457 



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

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

 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), f 

 They consist of a number of coiled 

 canals, presenting numerous simple 

 or compound, vesicular diverticula \  : ; \ 



(Fig. 179), and appear to be the \ ""'^h^'' '; < \ 



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 



^X:^ 



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, pyriform, 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 tlie floor of the oral cavity : a, investment of 

 connective tissue ; 6, excretory duct ; c, glandular vesicles ; d, 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. 



