STJBLINGUAL NERVE. 181 



tain that the main root is devoid of sensibility. They do 

 not, however, positively demonstrate the insensibility of the 

 ganglionic root, for a severe operation, it is well known, may 

 temporarily abolish the sensibility of nerves when this is not 

 very acute, as is seen in experiments upon the recurrent sen- 

 sibility of the anterior roots of the spinal nerves. Still, as 

 this filament is ordinarily absent in the human subject, there 

 can be little doubt that the sublingual at its origin js exclu- 

 sively motor. 



All modern experimenters have confirmed the observa- 

 tions of Mayo 1 and of Magendie, 2 with regard to the sensi- 

 bility of the sublingual after it has passed out of the cranial 

 cavity. The anastomoses of this nerve with the upper two 

 cervical nerves, the pneumogastric, and the lingual branch 

 of the fifth, afford a ready explanation of this fact. Accord- 

 ing to Bernard, this nerve possesses recurrent sensibility de- 

 rived from the fifth pair. 8 



The functions of the sublingual have already been so 

 fully considered under the head of deglutition, that they 

 need not be discussed elaborately in this connection. We 

 will here simply state the phenomena which follow stimula- 

 tion of the nerve and the division of both nerves in living 

 animals. 



The sublingual may be easily exposed in the dog by 

 making an incision just below the border of the lower jaw, 

 dissecting down to the carotid artery, and following the ves- 

 sel upward until we see the nerve as it crosses its course. 

 On applying a feeble current of galvanism at this point, 

 there are evidences of sensibility, and the tongue is moved 

 convulsively at each stimulation. 



The phenomena following section of both sublingual 



1 MAYO, Anatomical and Physiological Commentaries, Number ii., London, 

 1823, p. 11. 



8 MAGENDIE, Lecons sur les functions et les maladies du systeme nerveux, Paris, 

 1841, tome ii., p. 290. 



3 BERNARD, Lecons sur la physiologic et la pathologic du systeme nerveux, Paris, 

 1858, tome ii., p. 241. 



