CHAPTER XIV. 



THE SALIVARY GLANDS. 

 BY E. F. W. PFLUGEK. 



1. GENERAL PLAN OF STRUCTURE. The salivary glands 

 represented by the parotid, submaxillary and sublingual 

 glands, when examined with the naked eye, appear to be 

 rounded or polygonal yellowish-white masses, flattened by 

 mutual pressure, and opening by hollow peduncles into a 

 common excretory duct. The gland, in each instance, consists 

 of a tube branching frequently in a tree-like manner, and lined 

 throughout by a layer of epithelial cells. The numerous ter- 

 minal branches, named alveoli, are lined by large tesselated 

 epithelium, whilst the other portions are invested either 

 with columnar or small tesselated epithelium, and present a 

 clavate form, being arranged like grapes on the principal ex- 

 cretory duct. The salivary glands consequently belong to the 

 group of acinous glands. The alveoli, however, with their 

 secondary and tertiary processes, must not always be regarded 

 as possessing the form of a berry, since they not seldom appear 

 to be quite cylindrical, or only slightly contracted, where they 

 spring from the trunk. The number of alveoli belonging to 

 one of the smallest excretory ducts is so large that they lie 

 tightly compressed and flattened in a polygonal manner against 

 one another, leaving only a very small space for interstitial 

 tissue. 



THE ALVEOLI. If a section of the tubes measuring O030 

 millimeter in diameter be made, a canal and a wall may be 

 distinguished. Even in glands hardened in alcohol it may 

 easily be perceived that in the somewhat larger alveoli the 



