408 Mr. Bell’s experiments on the structure 
the face, neck, shoulders, and chest, in the actions of excited 
respiration, and are absolutely necessary to speech and ex- 
pression. But there are other nerves of the same class which 
go to the tongue, throat, and windpipe, no less essential to 
complete the act of respiration. These are the glossopha- 
ryngeal nerve, the lingual, or ninth of Willis, and the bran- 
ches of the par vagum to the superior and inferior larynx. 
We proceed to examine these nerves in detail, and first 
Of the nerves of the face, in which it is shown that the two sets of 
nerves , hitherto supposed to he similar , differ in structure, sensi- 
bility, and function.* 
It is in the face, that we have the best opportunity of ob- 
serving the subservience of the nerves to the uses of the parts, 
and of ascertaining the truth of the preceding doctrines. The 
human countenance performs many functions : in it we have 
combined the organs of mastication, of breathing, of natural 
voice and speech, and of expression. These motions are per- 
formed directly by the will ; here also are seen signs of 
emotions, over which we have but a very limited or imperfect 
controul ; the face serves for the lowest animal enjoyment, 
and partakes of the highest and most refined emotions. 
Happily for our present object, the nerves, which in other 
parts of the frame are bound together for the convenience of 
distribution to remote parts, are here distinct, and run apart 
from each other until they meet at their extremities. They 
take different courses through the bones of the head, and 
come out upon the face, to be exposed in a manner which 
courts enquiry. 
• This subject is illustrated by Plate XXX. which represents the nerves of the face. 
