VOLUNTARY MOTION. 4-97 



indeed the various movements of the extremities, head, and 

 trunk, which naturally are performed on various circumstances 

 presenting themselves, are just as instinctive; and we have only 

 to observe the movements of other animals, especially of those 

 most like ourselves, and above all of monkeys, to see how instinctive 

 our voluntary actions are, when we are most apt to regard them as 

 determined by our reflection. We contract all voluntary muscles 

 either simply because we think proper, as when we cough at the 

 request of another, or because a strong motive is given, as 

 when we withdraw the hand from any thing hot ; and the latter 

 is only such an instance as swallowing, coughing, winking, c. 

 when food is in the pharynx, phlegm in the larynx, or strong light 

 in the eyes. Certain sensations excite a certain desire, and this 

 may be too strong for us to overcome. But according to the 

 strength of mind will be the resistance to the strength of the desire 

 induced by the sensation. Some actions result from certain sens- 

 ations only, and we can neither perform some without these 

 sensations, nor when these sensations exist find it possible not 

 to yield to the desire. With some deglutition is not an act of 

 this kind. But sneezing is with all. I never knew a person able 

 to sneeze at pleasure. To be induced to will sneezing we must 

 have a certain sensation. If our attention is drawn to something 

 else, though the irritating cause act, we do not feel the sensation, 

 and do not sneeze. If the sensation is felt forcibly, the impulse 

 maybe too strong for us to resist, and sneezing will be involun- 

 tary : and we can bring ourselves to sneeze by attending closely 

 to the sensation, and by increasing it. I have often amused my- 

 self by looking more or less at the sun, or thinking more or less 

 of tickling felt at the moment in the nostrils, and so increasing 

 and lessening the inclination to sneeze. Without the sensation, 

 and a certain amount of it, .the sneezing no more than venereal 

 convulsion of the ejaculatores takes place. At the same time, 

 the facts discovered by Sir Gilbert Blane and others show a 

 connection between motion and impression independent of the 

 brain. But this is probably intended to assist the will in exciting 

 motions on the occurrence of impressions on individual parts ; and 

 the impression may be so strong that the will may be compelled 

 to determine the motion, and this compulsion will be according 

 to the strength of the impression and the weakness of opposing 

 motives and of the resolution to resist the inclination. Nay, these 



L L 2 



