624 NERVOUS SYSTEM. 



the opposite side ; but these phenomena do not occur unless the nerve be affected at its 

 root or within the aquseductus Fallopii. It is true that the uvula is frequently drawn to 

 one side or the other in persons unaffected with facial paralysis, but it is none the less 

 certain that it is deviated as a consequence of paralysis of the facial in some instances. 



Direct experiments upon the roots of the facial have not been followed by uniform 

 results. Debrou mentions one experiment in which galvanization of the facial within 

 the cranial cavity produced decided contraction of the muscles of the palate ; but, in 

 four others, the results were negative. Nuhn, however, produced contractions of these 

 muscles by galvanization of the nerve in the cranium in a man immediately after decapi- 

 tation. The experiments of Bernard upon this point are the most conclusive ; but while 

 they show, beyond a doubt, that the facial animates the movements of the soft palate, 

 they do not indicate the course of the filaments from the nerve to the muscles. In these 

 experiments, made in connection with M. Davaine, the whole of the velum palati was 

 exposed in a large-sized dog, by cutting through the hyoid bone. The trunk of the 

 glosso-pharyngeal nerve was then exposed in the neck, near its point of emergence at 

 the posterior foramen lacerum, and the animal was killed by section of the spinal cord 

 just below the origin of the cranial nerves. This being done, the glosso-pharyngeal was 

 galvanized, which produced violent contractions of the velum, the pillars of the fauces, 

 and a part of the pharynx, upon one side. The nerve was then divided, and galvanization 

 was applied to its peripheral end without producing any movement in the velum. The 

 central end was then galvanized, when the contractions were as vigorous as when the 

 nerve was intact. This result would lead to the supposition that contractions of the 

 muscles of the palate following galvanization of the glosso-pharyngeal are reflex and not 

 due to the direct action of filaments of distribution from this nerve. In a second experi- 

 ment, the parts were exposed in the same way, and, in addition, the facial was divided 

 upon the right side at its entrance into the internal auditory canal. The glosso-pharyn- 

 geal nerve was then galvanized upon the side on which the facial had been divided, with 

 the effect of producing movements of the pillars of the fauces, but not of the velum 

 palati itself. The glosso-pharyngeal was then galvanized upon the side on which the 

 facial was intact, which produced movements of the velum the same as in the first ex- 

 periment. Galvanization of the pneumogastric, the sublingual, and the lingual branch 

 of the fifth, failed to produce movements of the velum. 



" The first experiment proves that the glosso-pharyngeal nerve is not the motor nerve 

 of the velum palati, but that it induces reflex movements by the excitation which it 

 transmits to the nervous centre, an excitation which is carried to the parts by another 

 nerve. 



" The second experiment proves that the reflex movements of the velum palati, in- 

 duced by the excitation of the glosso-pharyngeal, are in part transmitted by the facial 

 nerve, the movements of the pillars not being produced by filaments belonging to this 

 nerve." 



Bernard also noted a fact, which has sometimes been observed in cases of facial 

 paralysis, that the point of the tongue is deviated after section of the facial ; which is 

 explained by the presence of a filament described by Hirschfeld, going from the facial to 

 the tongue. 



As we before remarked, the experiments of Bernard do not indicate the mode of 

 communication between the facial and the muscles of the palate. Longet regards the 

 filaments of the facial which influence the levator palati and azygos uvulae muscles as 

 derived from the large petrosal branch of the nerve, passing to the muscles through 

 Meckel's ganglion, the filaments to the palato-glossus and the palato-pharyngeus being 

 given off from the glosso-pharyngeal, but originally coming from an anastomosing branch 

 of the facial. As regards the branches of communication from the glosso-pharyngeal, 

 Longet mentions a preparation by Richet, in the museum of the Ecole de medecine, of 

 Paris, in which branches of the facial upon one side passed directly to the palato-glossus 



