GLOSSO-PHAKYNGEAL NEKVE. 243 



between its border and centre, and are distributed to the mu- 

 cous membrane at its base, being probably connected with the 

 papillae. 



General Properties of the Glosso-Pharyngeal. As in 

 the case of other sensory nerves emerging from the cranial 

 cavity, it is important, in studying the general properties of 

 the glosso-pharyngeal, to make our observations under certain 

 conditions. First, it must be remembered that this nerve 

 contracts anastomoses a short distance from its origin. As 

 we desire to know the properties of the original filaments of 

 the nerve, we must operate upon it before it has received 

 communicating fibres. Next, in irritating sensory nerves, we 

 are liable to produce reflex contractions. To avoid this, the 

 nerve must be divided ; when the reflex contractions will only 

 follow stimulation of the central end. It is probably from a 

 neglect of these essential experimental conditions, that the 

 results of direct observation have been so discordant in the 

 hands of different physiologists. 



To begin with, we shall assume that the glosso-pharyngeal 

 must be irritated between its origin and the ganglion of An- 

 dersch, in order to avoid anastomosing filaments from motor 

 nerves, and that the nerve must be divided, and irritation be 

 applied to its peripheral end, to avoid reflex movements. 

 Assuming these conditions as essential, we can discard most 

 of the earlier experiments, as open to the objections we have 

 mentioned. Longet, operating on horses and dogs, after re- 

 moval of the cerebral lobes and division of the glosso-pharyn- 

 geal, found that galvanization of the peripheral extremity of 

 the nerve did not produce movements of the palate or phar- 

 ynx ; * and, from these experiments, he concludes that the 

 nerves are exclusively sensory at their roots, or, at least, that 

 they do not contain motor filaments. This we accept as con- 

 clusive, notwithstanding the contrary assertion of Chauveau, 



1 LONGET, Anatomie et physiologic du systeme nerveux, Paris, 1842, tome ii., 

 p. 220 ; and, Traite de physiologic, Paris, 1869, tome iii., p. 601. 



