Ill 



thousandth part of a second, while my Balanced Cresco- 

 graph enables us to measure variation of rate of growth as 

 minute as , oVt> millionth of an inch per second, the sensi- 

 tiveness of this apparatus thus rivals that of the spectro- 

 scope. The increasing refinement in our experimental 

 methods cannot but lead to important advances towards 

 a deeper understanding of underlying reactions in the 

 living organism. 



I shall here draw attentioi to only a few of the 

 important results given in the present volume. The tropic 

 effect of light has been shown to have a definite rela- 

 tion to the quantity of incident light. A complete tropic 

 curve has been obtained from sub-minimal to maximal 

 stimulation which shows the inadequacy of Weber's law, 

 for the sub-minimal stimulus induces a qualitative differ- 

 ence in physiological reaction. It has further been shown 

 that the prevalent idea that perception and helioiropic 

 excitation are two distinct phenomena is without any 

 foundation. 



With reference to the effect of ether waves on plants, 

 1 have given an account of my discovery of the response 

 of all plants to wireless stimulation, the results being 

 similar to that induced by visible light. The perceptive 

 range of the plant is thus infinitely greater than ours ; 

 for it not only perceives, but also responds to different 

 rays of the vast ethereal spectrum. 



The results obtained by the method of geo-electric 

 response show that the responsive reaction of the root 



