and functions of the nerves. 417 
formidable disease, but complained that he could not whistle 
to his horses. 
Of the function of the trigeminus , or fifth nerve , as illustrated by 
these experiments . 
We have seen that when the fifth nerve, the nerve of 
mastication and sensation, was cut in an ass, the animal could 
no longer gather his food. In the individual whose face was 
paralyzed on one side during the excited state of the respi- 
ratory organs, there could be observed no debility or para- 
lysis in the same muscles when he took a morsel into his 
mouth, and began to chew. 
By an experiment made on the 16th of March, it was found, 
that on cutting the infra-orbitary branch of the fifth nerve on 
the left side, and the portio dura, or respiratory, on the right 
side of an ass, the sensibility to pain on the right side, where 
the portio dura of the seventh nerve was cut, remained en- 
tire, while that of the left side was completely destroyed by 
the division of the fifth. It was also apparent in this experi- 
ment, as in the others, that there was the most marked dif- 
ference in the sufferings of the animal, when these nerves 
were cut across. The cutting of the fifth nerve gave pain in 
a degree corresponding with our notions of the sensibility of 
nerves ; but in cutting the portio dura, it was not evident that 
the animal suffered pain at all. 
Independently of the difference of sensibility in these nerves, 
there was exhibited in all these experiments a wide distinc- 
tion in their powers of exciting the muscles. The slightest 
touch on the portio dura, or respiratory nerve, convulsed the 
muscles of the face, whilst the animal gave no sign of pain. 
