300 
Mr. Bell on the 
ment which was made in ignorance of the distinct functions 
of the nerves, and merely in correspondence with the order 
of succession in which they appear on dissection. 
The first nerve is provided with a sensibility to effluvia, 
and is properly called olfactory nerve. 
The second is the optic nerve, and all impressions upon 
it excite only sensations of light. 
The third nerve goes to the muscles of the eye solely, and 
is a voluntary nerve by which the eye is directed to objects. 
The fourth nerve performs the insensible traversing mo- 
tions of the eyeball. It combines the motions of the eyeball 
and eyelids, and connects the eye with the respiratory 
system. 
The fifth is the universal nerve of sensation to the head 
and face, to the skin, to the surfaces of the eye, the cavities 
of the nose, the mouth and tongue.* 
The sixth nerve is a muscular and voluntary nerve of the 
eye. 
The seventh is the auditory nerve, and the division of it, 
called portio dura, is the motor nerve of the face and eyelids, 
and the respiratory nerve, and that on which the expression 
of the face depends. 
* In this view of the fifth nerve, I have not touched upon its resemblance to the 
spinal nerves. But if we had ascended from the consideration of the spinal nerves 
to the nerves of the head, we should then have seen that the fifth was the spinal 
nerve of the head ; that it had a ganglion at its root, a double origin, and from its 
power over the muscles of the jaws and mastication, that it was a double nerve in 
function, being that nerve which bestows sensibility, at the same time that it sends 
branches to the original muscles ; that is to say, to that class of muscles which are 
common to animals in every gradation. In all these respects it resembles the 
spinal nerves. 
