THE GLOSSO-PHARYNGEAL NERVE. 555 



3. When the functions of the brain and medulla oblongata 

 were arrested by poisoning the animal with prussic acid, 

 irritation of the giosso-pharyngeal nerve, before it was 

 joined by any branches of the pneumogastric, gave rise to 

 no movements of the muscles of the pharynx or other parts 

 to which it was distributed ; while, on irritating the 

 pharyngeal branch of the pneumogastric, or the glosso- 

 pharyngeal nerve, after it had received the communicating 

 branches just alluded to, vigorous movements of all the 

 pharyngeal muscles and of the upper part of the oesophagus 

 followed. 



The most probable conclusion, therefore, may be that 

 what motor influence the glosso-pharyngeal nerve may 

 seem to exercise, is due either to the filaments of the 

 pneumogastric or accessory that are mingled with it, or to 

 impressions conveyed through it to the medulla oblongata, 

 and thence reflected to muscles through motor nerves, 

 especially the pneumogastric, accessory, and facial.^ Thus, 

 the glosso-pharyngeal nerve excites, through the medium 

 of the medulla oblongata, the actions of the muscles of 

 deglutition. It is the chief centripetal nerve engaged in 

 these actions ; yet not the only one, for, as Dr. John Reid 

 has shown, the acts are scarcely disturbed or retarded 

 when both the glosso-pharyngeal nerves are divided. 



But besides being thus a nerve of common sensation in 

 the parts which it supplies, and a centripetal nerve through 

 which impressions are conveyed to be reflected to the 

 adjacent muscles, the glosso-pharyngeal is also a nerve 

 of special sensation ; being the gustatory nerve, or nerve of 

 taste, in all the parts of the tongue to which it is distri- 

 buted. After many discussions, the question, which is 

 the nerve of taste ? the lingual branch of the fifth, or the 

 glosso-pharyngeal ? may be most probably answered by 

 stating that they are both nerves of this special function. 

 For very numerous experiments and cases have shown that 

 when the trunk of the fifth nerve or its lingual branch is 



