1588 



HUMAN ANATOMY. 



mon with other mucous glands, the sublingual lobules do not possess intralobular 

 tubules lined with the characteristic rod-epithelium. The interlobular ducts subdi- 

 vide into smaller canals which extend within the primary lobules and give off wider 

 passages lined with cubical epithelium. Towards the end of these terminal canals 



Fig. 1348. 



Duct 



Mucous alveoli 



Serous alveoli 

 Section of submaxillary gland, showing sesous and mucous alveoli. V. 2-jo. 



the mucous cells appear, at first isolated or in groups, increasing in numbers until 

 they form the entire lining of the passage and become the secreting elements occupy- 

 ing the tubular alveoli of the gland. The latter vary from .030-. 060 mm. in diam- 

 eter, and are clothed with cells averaging .015 mm. high. The condition of the 



Fig. 1349. 



Duct 



rescents of serous cells 



Section of sublingual gland, showing serous cells grouped as crescents. X 270. 



alveoli as regards the mucus-bearing cells varies greatly even in the same lobule. At 

 times an entire primary lobule is composed of acini filled with mucous cells ; at others 

 empty and gorged alveoli alternate, or the depleted acini may predominate. Uncer- 

 tainty as to the presence of the demilunes also exists, since these may be absent in 



