SECRETIONS 



93 



eluding potassium sulphocyanate), o. 1-0.4$ organic material 

 including proteids, mucin and a diastatic ferment, ptyalin, 

 and last of all, gases, especially carbon dioxide. 



2. Morphological phenomena accompanying salivary secre- 

 tion. The buccal cavity contains two kinds of glands: 



(a) Albuminous or serous glands furnish a secretion free 

 of mucin. To this class belong the parotid and, in many 

 animals (rabbits), the submaxillary also, and a part of the 

 glands of the mucous layer of the mouth-cavity. 



The cells of the albuminous glands have, during rest, a 

 small amount of clear, finely granular protoplasm and a 

 small irregular nucleus. In the active condition the cells are 

 smaller, the amount of the granular substance is increased, 

 and the nuclei become more nearly spherical. 



(/;) The mucous glands furnish a secretion containing 



i a, . a, 2 



*> 3 III. " 3 2 03 IV. 



FK;. 3. REPRESENTING THE ORIGIN OF DEMILUNES. (After St&hr.) 



mucin; this group contains all the glands except the albumi- 

 nous glands. 



Many glands, e.g. the sub-maxillary glands of man, con- 

 tain both albuminous and mucous gland-cells. 



In the mucous glands we find two kinds of cells : 



i. The demilune of Giannuzi (also called border cells) 



