THE GLOSSO-PHARYNGEAL NERVE. ^53 



tlieir ordinary functions. In an attempt to blow or whistle, 

 one side of the mouth and cheek acts properly, but the 

 other side is motionless, or naps loosely at the impulse of 

 the expired air ; so in trying to suck, one side only of the 

 mouth acts ; in feeding, the lips and cheek are powerless, 

 and food lodges between the cheek and gum. 



As a nerve of expression, the seventh nerve must not 

 be considered independent of the fifth nerve, with which it 

 forms so many communications ; for, although it is through 

 the facial nerve alone that all the muscles of the face are 

 put into their naturally expressive actions, yet the power 

 which the mind has of suppressing or controlling all these 

 expressions can only be exercised by voluntary and well- 

 educated actions directed through the facial nerve with the 

 guidance of the knowledge of the state and position of 

 every muscle, and this knowledge is acquired only through 

 the fifth nerve, which confers sensibility on the muscles, 

 and appears, for this purpose, to be more abundantly sup- 

 plied to the muscles of the face than any other sensitive 

 nerve is to those of other parts. 



Physiology of the Glosso-Pharyngeal Nerve. 



The glosso-pharyngeal nerves (i 6, fig. 1 5 1), in the enume- 

 ration of the cerebral nerves by numbers according to the 

 position in which they leave the cranium, are considered as 

 divisions of the eighth pair of nerves, in which term are in- 

 cluded with them the pneumogastric and accessory nerves. 

 But the union of the nerves under one term is inconvenient, 

 although in some parts the glosso-pharyngeal and pneumo- 

 gastric are so combined in their distribution that it is 

 impossible to separate them in either anatomy or phy- 

 siology. 



The glosso-pharyngeal nerve appears to give filaments 

 through its tympanic branch (Jacobson's nerve), to the 

 fenestra ovalis, and fenestra rotunda, and the Eustachian 



