248 SPECIAL SENSES. 



the flow of saliva, the reflex action involving chiefly the sub- 

 maxillary and sublingual glands; there is usually more or 

 less mastication, which increases the flow of the parotid 

 saliva ; and, during the acts of mastication and the first stages 

 of deglutition, the sapid substances are distributed over the 

 gustatory membrane, so much so, indeed, that it is difficult to 

 exactly locate the seat of the special impression. In this way, 

 by the movements of the tongue, aided by an increased flow 

 of saliva, the actual contact of the savory articles is rapidly 

 effected. The thorough distribution of these substances over 

 the tongue and the mucous membrane of the general buccal 

 cavity leads to a certain amount of confusion in our appre- 

 ciation of the special impressions ; and, in order to ascertain 

 if different portions of the membrane possess different prop- 

 erties, it is necessary to make careful experiments, limiting 

 the points of contact as closely as possible. This has been 

 done, with the result of showing that the true gustatory or- 

 gan is quite restricted in its extent, and, as such, it demands 

 special anatomical description. 



Physiological Anatomy of the Organ of Taste. Eecent 

 anatomical and physiological researches have shown that, at 

 least in the human subject, the organ of taste is probably 

 confined to the dorsal surface of the tongue. In the old ex- 

 periments of Yemiere and of Guyot and Admyrauld, quoted 

 and in part confirmed by Longet, 1 the gustatory sensibility of 

 the tongue was established ; and Longet, from observations 

 on his own person, touching different parts of the mucous 

 membrane with a sponge soaked in sapid solutions, came to 

 the following conclusions : "1. I cannot admit gustatory sen- 

 sibility in the mucous membrane which covers the superior 

 portion of the velum palati, nor for that which covers the 

 sublingual glands and the inferior surface of the tongue. 2. 

 I do not regard the superior and middle portion of the tongue 

 as absolutely devoid of this kind of sensibility." 



1 LONGET, Traite de physiologic, Paris, 1869, tome iii., p. 55. 



