THE NERVOUS SYSTEM. 145 



the upper part of the nasal cavities in which part alone the olfactory nerve 

 is distributed; because, to draw the air perfectly in this direction, the 

 action of the dilators and compressors of the nostrils should be perfect. 



Lastly, the sense of taste is impaired or may be wholly lost in paralysis 

 of the facial nerve, provided the source of the paralysis be in some part 

 of the nerve between its origin and the giving off of the chorda tympani. 

 This result, which has been observed in many instances of disease of the 

 facial nerve in man, appears explicable by the influence which, through 

 the chorda tympani, it exercises on the movements of the lingualis and 

 the adjacent muscular fibres of the tongue; and on the process of secre- 

 tion of saliva. 



Together with these effects of paralysis of the facial nerve, the muscles 

 of the face being all powerless, the countenance acquires on the paralyzed 

 side a characteristic, vacant look, from the absence of all expression: the 

 angle of the mouth is lower, and the paralyzed half of the mouth looks 

 longer than that on the other side; the eye has an unmeaning stare. All 

 these peculiarities increase, the longer the paralysis lasts; and their ap- 

 pearance is exaggerated when at any time the muscles of the opposite 

 side of the face are made active in any expression, or in any of their 

 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 flaps 

 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. 







GLOSSO-PHARYKGEAL NERVE. 



The glosso-pharyngeal nerves (16, Fig. 347), in the enumeration 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 included 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 pneumogastric are so 

 combined in their distribution that it is impossible to separate them in 

 either their anatomy or physiology. 



Distribution. The glosso-pharyngeal nerve gives filaments through 

 its tympanic branch (Jacobson's nerve,) to thefenestra ovalis, and fenestra 

 rotunda, and the Eustachian tube; also, to the carotid plexus, and, 

 through the petrosal nerve, to the spheno-palatine ganglion. After com- 

 municating, either within or without the cranium, with the pneumogas- 

 tric, and soon after it leaves the cranium, with the sympathetic, digastric 

 brunch of the facial, and the accessory nerve, the glosso-pharyngeal nerve 

 parts into the two principal divisions indicated by its name, and supplies 

 the mucous membrane of the posterior and lateral walls of the upper part 

 VOL. II. 10. 



