4 Mr. Bell’s experiments on the structure 
he turns out the edge of the lips as like a laugh as his organs 
can express. When the respiratory nerve on one side of the 
dog’s head was cut across, this motion of the lips no longer 
took place, although it was still observable on the other side, 
where the nerve was entire. 
On cutting the respiratory nerve on one side of the face of 
a monkey, the very peculiar activity of his features on that 
side ceased altogether. The timid motions of his eyelids and 
eyebrows were lost, and he could not wink on that side ; and 
his lips were drawn to the other side, like a paralytic drunkard, 
whenever he showed his teeth in rage. 
We have proofs equal to experiments, that in the human 
face the actions of the muscles which produce smiling and 
laughing, are a consequence of the influence of this respiratory 
nerve. A man had the trunk of the respiratory nerve of the 
face injured by a suppuration, which took place anterior to 
the ear, and through which the nerve passed in its course to 
the face. It was observed that, in smiling and laughing, his 
mouth was drawn in a very remarkable manner to the oppo- 
site side. The attempt to whistle was attended with a ludi- 
crous distortion of the lips; when he took snuff and sneezed, 
the side where the suppuration had affected the nerve remained 
placid, while the opposite side exhibited the usual distor- 
tion. 
Thus, it appears, that whenever the action of any of the 
muscles of the face is associated with the act of breathing, it 
is performed through the operation of this nerve. I cut a 
tumor from before the ear of a coachman : a branch of the 
nerve which goes to the angle of the mouth was divided. 
Some time after he returned to thank me for ridding him of a 
