

IV 



is in no way different from that of the shoot, the opposite 

 movements being due to the fact that in the shoot the 

 stimulation is direct, and in the root it is indirect. 



Full description is given of the new method of 

 physiological exploration by means of the electric probe, 

 by which the particular layer which perceives the 

 stimulus of gravity is definitely localised. The method 

 of electric probe is also found to be of extended applica- 

 tion in the detection of physiological changes in the 

 interior of an organ. 



An important factor of nyctitropic movements, hither- 

 to unsuspected, is the effect of variation of temperature 

 on geotropic curvature. This and other co-operative factors 

 have been fully analysed, and a satisfactory explanation 

 has been offered of various types of diurnal movement. 



A generalisation has been obtained which explains 

 all the diverse movements of plants, under all modes of 

 stimulation : it has been shown that dh^ect stimulation 

 induces contraction and reta^^dation of growth, atid that 

 indirect stimulation induces an expansion and acceleration 

 of growth. 



Another generalisation of still greater importance is the 

 establishment of identical nature of physiological reaction in 

 the plant and the animal, leading to advances in general 

 physiology. Thus the discovery of a method for immediate 

 enhancement or inhibition of nervous impulse in the plant 

 led to my success in the control of nervous impulse in the 

 animal. Another important discovery was the dual nervous 



