218 THE PHENOMENA OF MOTION 



It is further obvious, that if there should occur a dis- 

 proportion between the conducting power of the nerves of 

 voluntary and involuntary motion, a difference in the 

 phenomena of motion themselves will be perceptible, in 

 the same proportion as the one or the other is capable 

 of propagating the momentum of force, generated by 

 the change of matter. As the motions of the circulat- 

 ing system and of the intestines increase, the power of 

 producing mechanical effects in the limbs must diminish 

 in the same proportion (as in wasting fevers) ; and if, in 

 a given time, more vital force has been consumed for 

 mechanical purposes (labor, running, dancing, &c.) 

 than is properly available for the voluntary and involun- 

 tary motions ; if force be expended more rapidly than 

 the change of matter can be effected in the same time ; 

 then a part of that force which is necessary for the in- 

 voluntary motions must be expended in restoring the 

 excess of force consumed in voluntary motion. The 

 motions of the heart and of the intestines, in this case, 

 will be retarded, or will entirely cease. 



From the unequal degree of conducting power in the 

 nerves, we must deduce those conditions which are 

 termed paralysis, syncope, and spasm. Paralysis of 

 the nerves of voluntary motion may exist without ema- 

 ciation ; but frequently recurring attacks of epilepsy (in 

 which vital force is rapidly wasted in producing me- 

 chanical effects) are always accompanied by remarkably 

 rapid emaciation. 



It ought to excite the highest admiration when we 



