242 Mr. Shaw on the Facial Naves. 



branches of the first division of the Vth into the Imlbs of the 

 hairs over its eye-brow. 



It will be unnecessary to give more proofs from anatomy of 

 the distribution and use of this nerve being different from that of 

 the Portio Dura. I shall now corroborate them by mentioning 

 the result of two experiments. 



In the same ass, of which the Portio Dura, or facial respira- 

 tory nerve of the right side, had been cut, the infra orbital 

 branch of the Vth of the left side was divided. 



Upon cutting this nerve no change was produced in the action 

 of the muscles moving the left nostril in respiration, and this 

 could be easily observed, as the other nostril had been para- 

 lysed, by cutting the Portio Dura of the right side. The eflect, 

 however, upon the muscles of the lip during feeding was very 

 distinct, for although the same muscles were not paralysed in 

 the act of respiration, still they were rendered incapable of mas- 

 tication and voluntary motion, as the animal could no longer 

 use this side of his lip in gathering his food*. The sensibility 

 of this side was destroyed, for the animal did not start when 

 it was pricked with a needle, as he did when the other was 

 touched. I performed a similar experiment on a dog, which is 

 still alive. When he is quiet, the nose is twisted to the 

 side upon which the Vth is entire, and the Porizo Dura defi- 

 cient, but the moment he is excited, the nose is pulled to the 

 other side. 



* In an account which M. Magendie has given of some experiments 

 siniilar to those detailed in this paper, which he repeated at Cliarentou, he 

 says, " Le resultat que nous avous obtenu s'accorde parfaiteuieiit avec 

 celui que nous venous de rapporter, a I'exception touiefois, dc rinfluence 

 de la section du sous orbitaire sur la mastication, influence qui n'a pas 

 6t6 ^vidente pour moi." 



The idea that we had, in our experiments in England, found the power of 

 mastication destroyed, must have arisen from the difliculty I found of 

 expressing myself correctly in French, when discussing the results of the 

 experiments with M. Magendie. — There is one act of mastication destroyed 

 by cutting the infra orbital nerve, but to destroy the power altogether, it 

 would be necessary to cut through the trunk of the Vth nerve of each side. 



