EXPERIMENTAL PSYCHOLOGY 



initial discovery came the final understanding that the 

 entire nervous system is a mechanism of centres sub- 

 ordinate and centres superior, the action of the one of 

 which may be counteracted and annulled in effect by 

 the action of the other. This applies not merely to 

 such physical processes as heart-beats and arterial con- 

 traction and relaxing, but to the most intricate func- 

 tionings which have their counterpart in psychical 

 processes as well. Thus the observation of the inhibi- 

 tion of the heart's action by a nervous impulse fur- 

 nished the point of departure for studies that led to a 

 better understanding of the modus operandi of the 

 mind's activities than had ever previously been at- 

 tained by the most subtle of psychologists. 



PSYCHO-PHYSICS 



The work of the nerve physiologists had thus an im- 

 portant bearing on questions of the mind. But there 

 was another company of workers of this period who 

 made an even more direct assault upon the " citadel of 

 thought." A remarkable school of workers had been 

 developed in Germany, the leaders being men who, 

 having more or less of innate metaphysical bias as a 

 national birthright, had also the instincts of the em- 

 pirical scientist, arid whose educational equipment in- 

 cluded a profound knowledge not alone of physiology 

 and psychology, but of physics and mathematics as 

 well. These men undertook the novel task of interro- 

 gating the relations of body and mind from the stand- 

 point of physics. They sought to apply the vernier 

 and the balance, as far as might be, to the intangible 

 processes of mind. 



261 



