436 THE NERVOUS SYSTEM. 



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 of the pharynx, the Eustachian 

 tube, the arches of the palate, the tonsils and their mucous 

 membrane, and the tongue as far forwards as the foramen 

 caecum in the middle line, and to near the tip at the sides and 

 inferior part. 



Some experiments make it probable that the glosso-pharyn- 

 geal nerve contains, even at its origin, some motor fibres, to- 

 gether with those of common sensation and the sense of taste. 

 Whatever motor influence, however, is conveyed directly 

 through the branches of the glosso-pharyngeal, may be as- 

 cribed to the filaments of the pneumogastric or accessory that 

 are mingled with it. 



The experiments of Dr. John Reid, confirming those of 

 Panizza and Longet, tend to the same conclusions ; and their 

 results probably express nearly all the truth regarding the 

 part of the glosso-pharyngeal nerve which is distributed to the 

 pharynx. These results were that, 1. Pain was produced 

 when the nerve, particularly its pharyngeal branch, was irri- 

 tated. 2. Irritation of the nerve before the origin of its 

 pharyngeal, or of any of these branches, gave rise to extensive 

 muscular motions of the throat and lower part of the face: but 

 when the nerve was divided, these motions were excited by 

 irritating the upper or cranial portion, while irritation of the 

 lower end, or that in connection with the muscles, was followed 

 by no movement ; so that these motions must have depended 

 on a reflex influence transmitted to the muscles through other 

 nerves by the intervention of the nervous centres. 3. When 

 the functions of the brain and medulla oblongata were arrested 

 by poisoning the animal with prussic acid, irritation of the 

 glosso-pharyngeal nerve, before it was joined by any branches 

 of the poeumogastric, 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 com- 

 municating branches just alluded to, vigorous movements of 

 all the pharyngeal muscles and of the upper part of the oesoph- 

 agus followed. 



The most probable conclusion, therefore, may be that what 

 motor influence the glosso-pharyngeal nerve may seem to exer- 

 cise, is due either to the filaments of the pneumogastric or ac- 

 cessory 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 ex- 



