496 VOLUNTARY* MOTION. 



that an impression made upon any nerve of sensation, or, what 

 is the same thing, upon any part endowed with sensibility, may in- 

 duce action of any voluntary muscles calculated to remove it, if 

 disagreeable, or to be useful in some way to the individual, even 

 though the brain be prevented from perceiving the impression, 

 from having a sensation from the impression. The impression 

 need not be upon nerves running to the part of the encephalo- 

 spinal organs where the roots lie of the motor nerves excited, 

 for a sharp pinch of the toe will make a man not merely draw 

 away his foot, but raise his arms, make a face and halloa into the 

 bargain, whether he is asleep or awake. Tickling the sentient 

 twigs of the fifth pair, the eyelid, and cornea, is not requisite to 

 cause winking ; if by the optic nerve, one not included in Dr. M. 

 Hall's excito-motory class, we see a finger suddenly approach 

 the eye, instinctive, involuntary winking will as certainly occur. 

 Winking will occur if a strong light is suddenly admitted through 

 the lids to the retina of a person asleep. The sun's glare upon 

 the retina will excite sneezing. 1 " Not only are sneezing, vomiting, 

 sobbing, mentioned as acts of this system, but even deglutition, 

 which is declared always to be of this nature, and always to 

 require the presence of some stimulus to the sensible nerves of 

 the pharynx, it being " impossible to perform the act of swallow- 

 ing three or four times in rapid succession, without taking some- 

 thing into the mouth." Now if deglutition is always an excited 

 act, to use this gentleman's peculiar language, is always pro- 

 duced involuntarily by an impression on the pharynx, it must be 

 as impossible once or twice, without taking something into 

 the mouth, as three or four times, and slowly as rapidly. I, 

 however, can swallow with nothing in my mouth in rapid succes- 

 sion, as readily as with something, and above fifty times ; that 

 to say, till the muscles are fatigued. If swallowing is instinctive 

 when any thing reaches the pharynx, so is the act of opening the 

 mouth when a sugar-plum is offered to the eyes of a baby: and 



m Just as Dr. Fletcher considered the respiratory function of Sir C. Bell's ima- 

 ginary respiratory system of nerves, as only a part of its functions, its destination 

 being for sympathy at large, as well as for the sympathetic respiratory move- 

 ments, Dr. M. Hall considers Sir C. Bell's respiratory system of nerves as only 

 a part of his own peculiar excito-mctory system, which presides over respiration 

 as well as other excito-motory functions. The views of all these gentlemen 

 appear to me equally confined and erroneous. 



