214 THE HUMAN MOTOR 



in the course of my studies on fatigue," wrote Mosso, " is to have 

 discovered that the lowering of force, due to the action of thought 

 or of movement, produces identical effects. Whether man works 

 muscles or brain, the nature of the fatigue is always the same, 

 because there is only one actuating force in existence nervous 

 force." ( x ) 





f 1 ) A. Mosso (loc. cit., p. 216) ; W. Weichardt, Ueber ErdmUdungs-stoffe, 

 Stuttgart, 1910. 



