THE PAEOTID GLAND 



311 



with proper fixation, and in fresh tissue as well, can be demon- 

 strated within the meshes of the reticulum. These granules are 

 readily colored by the so-called specific mucin stains (Mayer's 

 muchematein and mucicarmine, safranin, and thionin). 



In the mucous cells the nucleus is crowded to the base or proxi- 

 mal end of the cell and flattened against the basement membrane. 

 It is surrounded by a small remnant of finely granular cytoplasm, 

 which, after the discharge of the mucus during secretion, is pre- 

 sumably capable of reloading the cell with its mutinous content. 



We will now consider the more important peculiarities of each 

 of the larger salivary glands. 



THE PAROTID GLAND. This is, in man,* the largest of the 

 salivary glands and is purely a serous secreting organ. The lob- 

 ules of the parotid 

 are firmly united 

 by dense but narrow 

 bands of connective 

 tissue which contain 

 the larger ducts, 

 blood vessels, lymph- 

 atics, and a few 

 small ganglia. 



The secreting 

 acini are relatively 

 long and tortuous; 

 they are frequently 

 branched or forked/" 

 Because of the rela- 

 tively low height of 

 their serous secret- 

 ing cells the acini 

 appear slender and their lumen is irregular, indistinct, and very 

 narrow. The " basket cells " upon which the secreting cells rest 

 are highly developed in the parotid and often form a complete 

 investment for the acinus. 



The acini of the parotid are all of one type. The only other 

 tubules within the lobules of this gland are the intercalary and 

 the intralobular or salivary ducts. The former are characterized 



FIG. 254. FROM A SECTION OF THE HUMAN PAROTID GLAND. 

 Z, lumen of a serous acinus ; sell, intercalary duct ; sr, 

 intralobular duct; T, secreting acini. Hematoxylin and 

 eosin. x 280. (After Sobotta.) 



* In the dog and a few other mammals the parotid has a mucinous secretion. 



