688 OF THE FUNCTIONS OF THE NERVOUS SYSTEM. 



section of the Lingual nerve on each side \ and it seems also well ascertained, 

 that it is impaired by section of the Glosso-pharyngeal nerve. The pathological 

 evidence bearing upon this point appears somewhat contradictory. Numerous 

 cases have been recorded, 1 in which both common and gustative sensation were 

 destroyed in the parts of the tongue supplied by the 5th pair, when that nerve 

 was paralyzed ; in some of these, the loss of the sense of taste appeared to ex- 

 tend itself to the base of the tongue, but then there was evidence that the Glosso- 

 pharyngeal was involved in the paralysis. On the other hand, cases of paralysis 

 of the 5th pair are related by Mr. Noble and by Vogt, 2 in which common sen- 

 sation was lost, whilst the sense of taste remained in the same parts ; and Mr. 

 Noble relates another case, 3 in which there was loss of taste without impairment 

 of common sensation. The cases of Mr. Noble and Vogt would seem to indicate 

 that the 5th pair does not minister to the sense of Taste ; but, as Dr. J. Reid 

 has justly observed, we have no evidence that all the filaments of the 5th Pair 

 sent to the tongue were affected ; and there is believed to be no case on record, 

 in which the whole of the 5th pair, or of its 3d branch, was found to be dis- 

 eased after death, and in which during life the sense of Taste had been retained 

 in the anterior and middle parts of the tongue. Hence these cases only serve 

 to indicate what is probable on other grounds ; viz., that the filaments which 

 convey gustative impressions are not the same with those that minister to com- 

 mon sensation. On the whole, then, it seems to be proved by anatomical and 

 experimental evidence, that both the Glosso-pharyngeal and the Fifth pair min- 

 ister alike to the tactile and to the gustative sense ; and there is nothing in the 

 pathological facts just noticed that militates against this conclusion. There 

 seems good reason to believe the Glosso-pharyngeal to be exclusively the nerve, 

 through which the impressions made by disagreeable substances taken into the 

 mouth are propagated to the Medulla Oblongata, so as to produce nausea and to 

 excite efforts to vomit. 



718. The functions of the Pneumogastric nerve at its roots have been made 

 the subject of particular examination by various experimenters ; some of whom 

 (for instance, Valentin, Longet, and Morganti) have concluded that it there 

 possesses no motor power, but is entirely a sensory or rather an afferent nerve. 

 According to these, if the roots be carefully separated from those of the Glosso- 

 Pharyngeal, and (which is a matter of some difficulty) from those of the Spinal 

 Accessory nerve, and be then irritated, no movements of the organs supplied by 

 its trunk can be observed : whilst, if the roots be irritated when in connection 

 with the nervous centres, muscular contractions, evidently of a reflex character, 

 result from the irritation ; and strong evidences of their sensibility are also 

 given. It has been further asserted that, when the roots of the Spinal Acces- 

 sory nerve are irritated, no indications of sensation are given ; but that the 

 muscular parts supplied by the Pneumogastric, as well as by its own trunk, are 

 made to contract, even when the roots are separated from the nervous centres ; 

 so that these roots must be regarded as the channel of the motor influence, trans- 

 mitted to them from the Medulla Oblongata. Where the Pneumogastric swells 

 into the jugular ganglion, an interchange of fibres takes place between it and 

 the Spinal Accessory ; and it seems clear that the pharyngeal branches, which 

 are among the most decidedly motor of all those given off from the Pneumogas- 

 tric, may in great part be traced backwards into the Spinal Accessory. But, on 

 the other hand, an equally numerous and trustworthy set of experimenters 

 (among whom may be mentioned J. Reid, Mliller, Volkmann, Stilling, Wagner, 



1 See especially the cases of Romberg, in " Mxiller's Archiv.," 1838, heft iii. ; Todd 

 and Bowman, in " Physiological Anatomy," p. 386, Am. Ed. ; and Dixon, in " Mod. Chir. 

 Trans.," vol. xxviii. 



2 " Medical Gazette," Oct. 25, 1834; and "Mailer's Archiv.," 1840, p. 72. 



3 " Medical Gazette," Nov. 21, 1835. 



