DIGESTION IN THE MOUTH. 



279 



The parotid saliva of the dog contains 1.818 and 1.701 pro.mil. 

 volumes of combined C0 2 . 



Salivaiy calculi are formed most usually in the parotid duct from 

 the deposition of lime salts, and contain no other ingredient of the 

 saliva. 



2. Tfie' Submaxillar y Secretion. — The saliva of the submaxillary 

 gland may be collected in man by inserting a small cannula in the opening 

 of the duet in the papilla of entrance at the side of the frsenum of the 

 tongue, or by aspirating it by a small syringe whose nozzle will grasp 

 the papilla air-tight. In animals the maxillary saliva ma}' be collected 

 by means of a permanent or temporary fistula of the duct of Wharton. 



Fig. 115.— Operation of Isolating the Duct of the Submaxillary 

 Gland in the Dog. (Bernard.) 



a, digastric muscle drawn to one side ; h, mylo-hyoid muscle divided and drawn to one side ; c e, duct of 

 Wharton ; d, duct of the sublingual gland ; 1, lingual nerve. 



To discover the submaxillary duct before its entrance into the mouth, after 

 etherization, the hair is shaved from the under surface of the lower jaw, an 

 incision made along the inner border of the ramus of the lower jaw from the 

 anterior insertion of the digastric muscle forward for about two inches, dividing 

 the skin and platysma, every vein that comes into view being tied with two 

 ligatures and divided between them. The niylo-hyoid muscle is then in view, and 

 is to be very cautiously divided at its middle, avoiding the mylo-hyoid nerve, 

 which lies upon it. If the portion still in connection with the ramus of the jaw 

 is elevated, the submaxillary and sublingual ducts will be found running forward 



