172 On the Relations between Mind and Muscle. 



Or his nervous derangement may be of a different kind. He may experi- 

 ence the sensation of being himself tossed np and down, or whirled round 

 and round; when his support is in reality most secure, and his muscles are 

 in a state of inaction, as for instance, in the recumbent posture. Many per- 

 sons have known this feeling after inhaling tobacco for the first time ; and 

 it is said to occur to the drunkard, either when staggering and reeling, or 

 when prostrate on the ground. 



It would seem that in some cases of vertigo, t\\e feeling of giddiness is 

 not a perverted one, but that the disorder of the nervous system relaxes 

 the muscles which usually preserve the erect posture ; and that upon this 

 relaxation the body is in peril of falling, and is felt to be so. In this in- 

 stance the sensation is a true one, that is, indicates the actual condition of 

 the body. The individual thus affected, catches at some support with his 

 tipper extremities, which perform the duty of the lower ones. 



In the lower animals the motions of equilibration are sooner developed 

 than in ourselves. The kid follows its mother on the mountain side on the 

 very day of its birth j and the chicken walks as soon as it has left the 

 shell; but the child suffers many disappointments before the feeling in 

 question is followed by its apjjropriate motions. 



It would be interesting to enter into further details upon this subject, 

 but enough lias, we hope, been said to shew that desire or volition has no 

 necessary connection with the actions that belong to equilibrium. 



3. The next class of instinctive motions are those immediately consequent 

 upon external sensations. — A remarkable instance is the suction of the 

 infant. The simple sensation produced in the lips induces those beautifully 

 connected actions of the muscles of the tongue, mouth, and pharynx, which 

 extract the nutritive fluid. Sometimes the mere tactual impression is 

 sufficient ; at others it is necessary that the taste should be excited. No 

 one can for a moment suppose that the infant exerts any volition or feels a 

 desire for the muscular movement in question. If from any circumstance 

 the fluid excite disagreeable sensations, his muscles do not act. When he 

 lias become familiar with the gratification, he appears to have the power of 

 increasing the actions ; i. e. he remembers the motions which have formerly 

 produced enjoyment, and desires their repetition to a degree which 

 wonderfully increases their energy. He also becomes able to suspend 

 them either from mere caprice, or from other motives, even when the sen- 

 sation which was wont to provoke the action, is scarcely less agreeable 

 than formerly. In aniiuals this kind of instinctive movement consequent 

 on sensation is very remarkable. The lamb just born follows its mother by 

 sight; the blind puppy by scent; and the newly-hatched chicken pecks 

 at grain. Another example of the class before us is the motion which 

 follows an impression of pain. Place a hot body on the hand of a person 

 in deep thought, and the latter is retracted immediately. If a person 

 walking rapidly round a corner, happens to come suddenly upon the margin 



