Human physiology : designed for colleges and the higher classes in schools and for general reading . the mind. 246. In the face we have an example of different sets ofnerves for different classes of motions. All those motions thatare used in the expression of the countenance are associatedtogether by a certain nerve. This nerve has nothing to dowith other motions, as mastication. Other nerves are providedfor them. Sometimes this nerve of expression is paralyzed onone side. The result is, that while the individual can masti-cate equally well on both sides, he can laugh, and cry, andfrown, only
Human physiology : designed for colleges and the higher classes in schools and for general reading . the mind. 246. In the face we have an example of different sets ofnerves for different classes of motions. All those motions thatare used in the expression of the countenance are associatedtogether by a certain nerve. This nerve has nothing to dowith other motions, as mastication. Other nerves are providedfor them. Sometimes this nerve of expression is paralyzed onone side. The result is, that while the individual can masti-cate equally well on both sides, he can laugh, and cry, andfrown, only on one side, and he can not close the eye on the sideaffected. In Fig. 82 is a representation of this condition ofthings. The left eye can not be closed by any effort, and theleft side of the face is wholly devoid of expression. This nerveof expression is often paralyzed by itself, the other nerves in theneighborhood, both nerves of sensation and of motion, beingentirely unaffected. This nerve has been called the respiratory THE NERVOUS SYSTEM. 157 Pnralysis of the respiratory nerve of the PARALYSIS OF THE NERVE OF EXPRESSION on one side of the face. nerve of the face, because it controls motions which are con-nected with the movements of respiration. If you observe howthe various passions and emotions are expressed, you will seethat there is a natural association between the muscles of theface and those of the chest in this expression. This is veryobvious in laughing and in weeping. But this association canbe effected only through nervous connections. And these con-nections in this case are very extensive and intimate. Whenthe nerve of expression, or facial respiratory nerve, is par-alyzed, all the motions of the face connected with the respi-ration are absent. Though the individual may sob in weep-ing, or send forth the rapid and successive expirations oflaughter, yet the face on the side where the nerve is par-alyzed will be perfectly quiescent. So, too, those movemen
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