236 SPECIAL SENSES. 



and these observations leave no doubt of the fact that the 

 chorda tympani is really distributed to the lingual mucous 

 membrane. Observations on the sense of taste show that 

 the chorda tympani is distributed to about the anterior two- 

 thirds of the tongue. 



The general properties of the chorda tympani have only 

 been ascertained by observations made after its paralysis or 

 division. All experiments, in which excitation has been ap- 

 plied directly to the nerve in living animals, have been nega- 

 tive in their results. Longet states that, when the nerve has 

 been isolated as completely as possible, and all reflex action is 

 excluded, its galvanization produces no movement in the 

 tongue. 1 



For a long time, the lingual branch of the inferior maxil- 

 lary division of the fifth has been regarded as a nerve of 

 taste, and has been called the gustatory branch. In 1786, 

 Caldani noted, in an affection of the fifth pair, called " cynic 

 spasm," loss of the sense of taste. 2 In 1818, Bellingeri dis- 

 cussed the question whether the sense of taste in the tongue 

 was derived from proper filaments of the fifth pair or from 

 filaments passing to the fifth from the seventh by the chorda 

 tympani, and came to the conclusion that the gustatory sense 

 was due to the filaments of the chorda tympani. 8 In 1821, 

 Professor Roux described his own case of paralysis of the 

 facial, and noted that " the sense of taste was affected in the 

 right side of the tongue, so that every thing tasted metallic ; 4 

 but, in this observation, no mention was made of the chorda 

 tympani. In 1831, Montault noted loss of taste in deep palsy 

 of the facial and explained it by indicating an affection of 

 the chorda tympani. 5 Since that time, it has been established 



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



2 CALDANI, Institutiones Physiological, Venetiis, 1786, p. 163. 



3 BELLINGERI, Dissertatio Inaugurates, Quinti, et Septimi Paris Functiones, 

 1818, p. 170. 



4 BELL, The Nervous System of the Human Body, London, 1844, p. 329. 



5 MONTAULT, Dissertation sur Vhemiplegie faciale, These, No. 300, Paris, 1831, 

 p. 22. 



