164 DIGESTION. 



The submaxillary gland pours out its secretion in great- 

 est abundance when sapid substances are introduced into 

 the mouth. Bernard io of the opinion that the function of 

 this gland is connected exclusively with gustation, and that 

 secretion never takes place except in obedience to stimula- 

 tion of the gustatory nerves. 1 It is undoubtedly true that the 

 most marked influence of sapid substances is upon the sub- 

 maxillary gland, and that this is the case in dogs has been 

 sufficiently proven by experiments. In the solipeds and 

 ruminants, Colin has observed that the quantity of submax- 

 illary saliva secreted is much increased during eating ; but, 

 unlike the parotids, the secretion does not alternate on the 

 two sides with the alternation in mastication. He has 

 found in all the domestic animals, that the flow is greatly 

 influenced by the degree of sapidity of the food. 2 As regards 

 the special functions of the different salivary glands, it is im- 

 possible to reason directly from the inferior animals to the 

 human subject ; and the distinction which Bernard has en- 

 deavored to establish between the different glands is undoubt- 

 edly too rigorous. Although sapid articles induce an abun- 

 dant secretion from the submaxillary glands, they also pro- 

 duce an increase in the secretions from the parotids and sub- 

 linguals ; and, 011 the other hand, movements of mastication 

 increase somewhat the flow from the submaxillaries, and 

 these glands secrete a certain amount of fluid during the 

 intervals of digestion. The viscid consistence of the sub- 

 maxillary saliva renders it less capable of penetrating the 

 alimentary mass during mastication than the parotid secre- 

 tion, so that it remains chiefly on or near the surface of the 

 bolus. 



S'ublingual Saliva. The sublinguals, the smallest of 

 the salivary glands, are situated beneath the tongue, on ei- 



1 Op. tit., p. 85. 



>J COLIN, Traite de Physiologie Comparee des Animaux Domestiques, Paris, 

 1854, tome i., p. 473. 



