INSALIVATTON. 165 



ther side of the frenum. In minute structure they resemble 

 the parotid and the submaxillary glands. Each gland has a 

 number of excretory ducts, from eight to twenty, which 

 open into the mouth by the side of the frenum ; one of the 

 ducts, larger than the others, joins the duct of the submax- 

 illary gland near its termination in the mouth. 



The secretion of the sublingual glands is more viscid 

 even than the submaxillary saliva ; but it differs in the fact 

 that it does not gelatinize on cooling. It is so glutinous that it 

 adheres strongly to any vessel, and flows with difficulty from 

 a tube introduced into the duct. Like the secretion from the 

 other salivary glands, its reaction is distinctly alkaline. Its 

 organic matter is not coagulated by heat, acids, nor the 

 metallic salts. According to Bernard, after desiccation it is 

 redissolved by water, and its viscid properties are then re- 

 stored. 1 



In accordance with the view entertained by Bernard 

 concerning the function of this variety of saliva and its spe- 

 cial connection with deglutition, it is supposed to be secreted 

 immediately before and during the act of swallowing. The 

 experiments which are advanced in support of this view are 

 mostly those in which a tube was fixed in each of the three 

 salivary ducts in a dog ; when the animal was caused to make 

 movements of the jaw, movements of deglutition, and at the 

 same time the gustatory nerves were stimulated by the intro- 

 duction of vinegar into the mouth. In an experiment of 

 this kind, it was observed that fluid was secreted by all the 

 glands, but in unequal proportions ; " the submaxillary sali- 

 va flowed very abundantly, the parotid saliva much less, and 

 the sublingual saliva flowed very feebly." 2 Although the 



1 BERNARD, op. cit., p. 92. 



Bernard gives a table of the composition of the sublingual saliva taken from 

 Bidder and Schmidt. This is an error. The table referred .to is the composi- 

 tion of the mucous secretion of the mouth (Mundschleiiri) ; and the authors re- 

 ferred to only analyzed, as distinct secretions, the parotid and sublingual saliva, 

 the compositions of which have been given. (Die Verdauungssafte, etc., S. 5.) 



2 BERNARD, op. cit., p. 81. 



