ON NERVOUS ENERGY 61 



muscles are stimulated but not contracted. This con- 

 dition enables the fighter to reduce the period of latent 

 contraction the period which elapses between the stimu- 

 lation and contraction of the muscle to the lowest limit, 

 since the already stimulated muscle contracts almost 

 instantaneously on receiving the additional stimulus, and 

 thus enables him to seize in a flash any opening that 

 occurs. But this maintenance of the muscles in a state 

 of latent stimulation requires an enormous expenditure 

 of nervous energy. It would be clearly impossible for 

 the fighter to expend energy on such a scale for such a 

 length of time if his training did not increase the amount 

 available. Quite apart from this question of latent 

 stimulation, to train the muscles of a prize-fighter without 

 increasing the amount of nervous energy available would 

 be very like increasing the supply of dynamite cartridges 

 without increasing the supply of detonators. The analogy 

 is not quite exact, since the trained muscle contracts 

 with greater force in response to a given stimulus, and 

 thus economises nervous energy to a considerable extent. 

 But such economy goes but a trifling way towards explain- 

 ing the wonderful endurance shown by trained men in 

 contests in which muscular strength and nervous energy 

 are expended with the utmost prodigality, the nervous 

 system being drawn upon more and more largely as the 

 muscles become exhausted. 



Again, the effects of exercise on the nervous system 

 can be readily seen in the difference between the average 

 town-bred man and the average country-bred man. The 

 environment and occupation of the former call for con- 

 siderable mental alertness and usually for activity of 

 movement rather than the exertion of great muscular 

 strength. The environment of the latter and his occupa- 

 tion call for no special mental alertness or activity of 



