ANIMAL AUTOMATISM v 



the viscera which accompany intense emotion, to 

 these organs. It proves, directly, that those 

 states of consciousness which we call sensations 

 are the immediate consequent of a change in the 

 brain excited by the sensory nerves ; and, on the 

 well-known effects of injuries, of stimulants, and 

 of narcotics, it bases the conclusion that thought 

 and emotion are, in like manner, the consequents 

 of physical antecedents. 



II. The movements of animals are due, to the 

 change of form of muscles, which shorten 

 and become thicker; and this change of 

 form in a muscle arises from a motion of 

 the substance contained within the nerves 

 which go to the muscle. 



In the " Passions de 1'Ame," Art. vii., Descartes 

 writes : 



"Moreover, we know that all the movements of the limits 

 depend on the muscles, and that these muscles are opposed to 

 one another in such a manner, that when one of them shortens, 

 it draws along the part of the body to which it is attached, and 

 so gives rise to a simultaneous elongation of the muscle which 

 is opposed to it. Then, if it happens, afterwards, that the latter 

 shortens, it causes the former to elongate, and draws towards 

 itself the part to which it is attached. Lastly, we know that all 

 these movements of the muscles, as all the senses, depend on the 

 nerves, which are like little threads or tubes, which all come 

 from the brain, and, like it, contain a certain very subtle air or 

 wind, termed the animal spirits." 



The property of muscle mentioned by Descartes 



