408 



ORGANS OF THE SENSES. 



ally acknowledge the sensory functions of the chorda tympani. 

 The most recent experiments on this subject are those made by 

 Vulpian, who considers the filaments leading from this nerve to the 

 tongue as similar to those which pass from it to the sub-maxillary 

 gland (Soc. de Biologic, 187;>). By exciting these filaments in the 

 corresponding half of the organ, Vulpian produced phenomena 

 similar to those which take place in the sub-maxillary gland dur- 

 ing the galvanization of the same nerve; in other words, the tongue 

 grows red and heated on the side galvanized. The chorda tympani 

 is, therefore, a vaso-motor nerve, which here also regulates the 

 dilatation of the vessels (see p. 174J). We see in this way how 

 facial paralysis may att'ect the sense of taste, the function of the 

 lingual mucous being undoubtedly influenced by the vascularization 

 of this tissue. 



III. SENSE OF SMELL. 



The sense of smell is one which gives rise to certain per- 

 ceptions known as odors ; it is, however, still more difficult 



Fig. 107. External wall of the nasal chambers with the three spongy 

 or turbiuated bones and the three meatus.* 



to define exactly an odorous substance, and the nature of the 

 impressions produced by it, than to define a sapid substance 



* a, Olfactory nerve, b, Olfactory bulb upon the cribiform plate of the 

 ethmoid: below is seen the plexiform disposition of the olfactory branches upon 

 the upper and the middle turbinated bones, c, Nerve of the fifth pair, with 

 (Jussc'riaii ganglion. , Its palatine branches ( upper maxillary and their pitui- 

 tary lilaments. 



