410 Mr. Bell’s experiments on the structure 
the nerve splits into three great divisions, which are sent to 
the face, jaws, and tongue. Its branches go minutely into the 
skin and enter into all the muscles, and they are especially 
profuse to the muscles which move the lips upon the teeth. 
Of the respiratory ?ierve of the face , being that which is called 
portio dura of the seventh * ( Plate XXX. A abed). 
This nerve does not exist except where there is some 
consent of motions established betwixt the face and the re- 
spiratory organs. In fishes, this nerve, instead of being 
distributed forward to the face, passes backward to the mus- 
cles of the gills. In fact, there is, properly, no portio dura 
of the seventh in fishes, the nerve resembling it being a 
branch of the par vagum. A short description of this nerve 
in the human body will be necessary to our enquiry. 
The respiratory nerve of the face arises from the superior 
and lateral part of the medulla oblongata , close to the nodus 
cerebri, and exactly where the crus cerebelli joins the medulla 
oblongata. The other respiratory nerves, which form so dis- 
tinguished a part of the nervous system, arise in a line with 
the roots of this. 
The nerve, passing into the internal auditory foramen, is 
here embraced by the portio mollis ; but it separates from it, 
and is received into an appropriate canal of the temporal bone. 
A little farther on, and while within the temporal bone, two 
cords of communication are formed with the branches of the 
fifth nerve, or trigeminus. One of these is called Vidian 
nerve, and the other corda tympani. By these communications, 
* Portio dura nervi acustici . Sympatbeticus parvus by Winslow, Faciale by 
Vicq. d'Azyr. 
