418 Mr. Bell’s experiments on the structure 
By means of the branches of the fifth nerve, it was more 
difficult to produce any degree of action in the muscles, al- 
though, as I have said, touching the nerve gave great pain. 
I divided the branch of the fifth pair, which goes to the 
forehead, in a man, at his urgent request, on account of the 
tic doloureux : there followed no paralysis of the muscles of 
the eyebrow ; but in an individual where an ulcer and abscess 
seated anterior to the tube of the ear affected the superior 
branch of the respiratory nerve, the eyebrow fell low, and did 
not follow the other when the features were animated by 
discourse or emotion. 
It will be asked, why a nerve called respiratory , should go 
to the ear and the eye ? First, let us enquire, does it belong 
to the frame of animal bodies that there shall be in them indi- 
cations of passion ? If it be admitted that this is the case, we 
here learn in addition, that as the portio dura is the nerve of 
respiration, so is it the grand nerve of expression, not only in 
man, but in brutes also. All that excitement seen in a dog’s 
head, his eyes, his ears, when fighting, disappears, if this 
nerve be cut. The respiratory nerve being cut across in a 
terrier, the side of the face was deprived of all expression, 
whether he was made to crouch, or to face an opponent and 
snarl. When another dog was brought near, and he began 
to snarl and expose his teeth, the face, which was balanced 
before, became twisted to one side, to that side where the 
nerve was entire; and the eyelids being, in this state of ex- 
citement, very differently affected, presented a sinister and 
ludicrous expression- 
On cutting the respiratory nerve of the face in the carni- 
vorous animals, it did not appear that the action of feeding 
