xil COMPARATIVE ELECTRO-PHYSIOLOGY 



of psychical processes." Such arbitrary lines can hardly 

 be drawn. 



' We may explain each of the above classes of phenomena 

 by making numerous and independent assumptions ; or, 

 finding some property of matter common and persistent 

 in the living and non-living substances, attempt from this 

 common underlying property to explain the many phe- 

 nomena which at first appear so different. And for this 

 it may be said that the tendency of science has always 

 been to attempt to find, wherever facts justify it, an under- 

 lying unity in apparent diversity.' 



It was for the demonstration of this underlying unity 

 that I set out on these investigations seven years ago. 

 And now, in bringing to its close another stage of their 

 publication, I may, perhaps, be permitted to express the 

 hope that by them not only may a deeper perception of 

 this unity have been made attainable, but also that many 

 regions of inquiry may prove to have been opened out, which 

 had at one time been regarded as beyond the scope of experi- 

 mental exploration. 



I take this opportunity to thank my assistants for their 

 efficient help in these researches. 



J. C. BOSE. 



PRESIDENCY COLLEGE, CALCUTTA : 

 August 1906. 



