THE SALIVARY GLANDS 



137 



FIG. 166. DIAGRAM OF THE CONSTRUCTION OF A LOBULE OF A TUBULO-RACEMOSE 

 (ACINO-TUBULAR) MUCOUS GLAND. 



a, duct ; 6, a branch of the duct ; e, alveoli as they lie together in the gland ; d, the same 

 separated, showing their connection as an irregular tube. 



FIG. 167. MEMBRANA PROPRIA OF TWO ALVEOLI ISOLATED. 



The preparation is taken from the orbital gland of the dog, which is similar in structure to a 

 mucous salivary gland. 



FIG. 168. SECTION OF THE SUBMAXILLARY GLAND OF THE DOG, SHOWING THE 

 COMMENCEMENT OF A DUCT IN THE ALVEOLI. (Magnified 425 diameters.) 



a, one of the alveoli, several of which are in the section shown grouped around the 

 commencement of the duct, d' ; nr', an alveolus, not opened by the section ; 6, basement- 

 membrane in section ; c, interstitial connective tissue of the gland ; d, section of a duct 

 which has passed away from the alveoli, and is now lined with characteristically striated 

 columnar cells ; *, semilunar group of darkly stained cells at the periphery of an alveolus. 



