EXPERIMENTAL PSYCHOLOGY 



was fresh from the press, steps were being taken to ex- 

 tend the methods of the physicist in yet another way 

 to the intimate processes of the mind. As Helmholtz 

 had shown the rate of nervous impulsion along the 

 nerve tract to be measurable, it was now sought to 

 measure also the time required for the central nervous 

 mechanism to perform its work of receiving a mes- 

 sage and sending out a response. This was coming 

 down to the very threshold of mind. The attempt 

 was first made by Professor Bonders in 1861, but 

 definitive results were only obtained after many 

 years of experiment on the part of a host of ob- 

 servers. The chief of these, and the man who has 

 stood in the forefront of the new movement and 

 has been its recognized leader throughout the re- 

 mainder of the century, is Dr. Wilhelm Wundt, of 

 Leipzig. 



The task was not easy, but, in the long run, it was 

 accomplished. Not alone was it shown that the nerve 

 centre requires a measurable time for its operations, but 

 much was learned as to conditions that modify this 

 time. Thus it was found that different persons vary in 

 the rate of their central nervous activity which ex- 

 plained the "personal equation" that the astronomer 

 Bessel had noted a half -century before. It was found, 

 too, that the rate of activity varies also for the same 

 person under different conditions, becoming retarded, 

 for example, under influence of fatigue, or in case of 

 certain diseases of the brain. All details aside, the es- 

 sential fact emerges, as an experimental demonstration, 

 that the intellectual processes sensation, appercep- 

 tion, volition are linked irrevocably with the ac- 



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