156 NEKVOUS SYSTEM. 



nerve be simply enclosed in the sheath of the lingual branch 

 of the fifth or be so closely connected with it that it cannot 

 be traced to a distinct distribution. Upon this point we are 

 disposed to adopt the opinion of Sappey, who, as the result 

 of minute dissections, regards the union as complete, " fibril 

 to fibril." As regards the portion of the facial which fur- 

 nishes the filaments of the chorda tympani, it is impossible 

 to determine anatomically whether these come from the 

 main root or from the intermediary nerve of Wrisberg, as 

 the fibres of these roots are closely united before the chorda 

 tympani is given off. 1 



Concerning the general properties of the chorda tym- 

 pani, it is curious to note the opposite opinions of different 

 physiologists ; some regarding it as a motor nerve, others 

 as purely sensitive, and others as a special nerve of taste. 

 When we come to analyze the actual experimental observa- 

 tions upon the nerve, it is seen that it cannot be regarded 

 as an ordinary motor nerve ; for galvanization of the root 

 of the facial before this branch is given off, and careful gal- 

 vanization of the chorda tympani itself, produce not the 

 slightest movement in the tongue. 2 The operative proced- 

 ure necessary to expose the parts is so severe as to render 

 observations with regard to its sensibility very unsatisfac- 

 tory. It is certain, however, that it is not an acutely sen- 

 sitive nerve like the fifth, or like certain branches of the 

 pneumogastric. 



The only questions that we propose fo consider in this 

 connection relate to the functions of the chorda tympani as 

 a nerve of gustation, and as it influences the secretion of the 

 submaxillary gland. 



There can be no doubt with regard to the influence of 

 the chorda tympani upon the sense of taste in the anterior 

 portion of the tongue. "Without citing all of the experi- 

 ments and pathological observations bearing upon this ques- 



1 SAPPEY, Traite d'anatomie, Paris, 1852, tome ii., p. 258. 



2 LONGET, Traite de physiologic, Paris, 1869, tome iii., p. 581, note. 



