1888.] On the Motor Functions of certain Cranial Nerves. 271 



from the facial to the levator palati through the superficial petrosal 

 nerve. 



This idea,* upon which so much stress has been laid, is entirely 

 hypothetical, as might have been shown at any time by stimulating 

 the facial nerve in the skull, and observing the soft palate. 



We have found that stimulation of the peripheral end of the 

 divided facial nerve in the internal auditory meatus failed to cause 

 even with most powerful currents the slightest movement of the 

 soft palate, although the face was thrown into violent spasm. The 

 true motor nerve supply of the levator palati is, according to our 

 observations, the Xlth nerve (vide infra). 



IXth Nerve. Glossopharyngeal. — In exciting this nerve, in addi- 

 tion to the movements of the pharynx, which we attribute to the 

 contraction of the stylopharyngeus, and possibly to the middle con- 

 strictor of the pharynx, we have observed certain movements of the 

 palate, as follows : — (I.) Stimulation of the nerve while beneath the 

 stylohyoid ligament and uncut, gave in two instances elevation of 

 the palate on the same side, and in one instance on both sides. We 

 suppose that everyone will consider with us this movement to be 

 reflex in origin, but we must add (II) that in one case we saw eleva- 

 tion of the palate to the same side when exciting the peripheral end 

 of the cut nerve. In this latter case, perhaps, the result may be 

 explained by the close neighbourhood of the pharyngeal plexus and 

 the possible escape of current thereto, and under any circumstances 

 this is but a single exceptional observation, so that we lay no stress 

 upon it. Finally we never saw movement of the soft palate when 

 the glossopharyngeal nerve was stimulated within the cranial 

 cavity. 



Xth Nerve. Vagus. — In stimulating the uncut nerve outside the 

 skull, below the level of its junction with the hypoglossal, 

 rhythmical movements of swallowing were produced, which occurred 

 at the rate of twenty-five times in thirty-five seconds. 



In one observation all the constrictors of the pharynx were thrown 

 into action, when the peripheral end of the cut nerve was stimulated 

 outside the skull. 



The rhythmical movements of swallowing obtained by stimulating 

 this nerve must be due to, of course, the simple reflex, the stimulus 

 acting on the nerve in the centripetal direction, and that this was 

 the case is proved by the fact that no movement was obtained when 

 the peripheral end of the cut nerve was stimulated inside the skull. 



* Without definitely supporting this view, G-askell ('Roy. Soc. Proc.,' vol. 43, 

 p. 390) shows that some large " somatic " nerve-fibres leave the facial nerve between 

 its origin from the bulb and its exit from the stylomastoid foramen. He suggests 

 that some of them may possibly form a nerve to supply the levator palati, but he 

 leaves their real destination undetermined. 



