61 



will be stated in Chapter III. wheie also Blackman's 

 ideas will be tested by tlie facts. 



î^ 10. Summary and discussion of reaction-timos. 



It was already pointed out, tliat in this investigation it 

 was not intended to trace the influence of température 

 upon the reaction -time. For this reason I ani only able 

 to deal with this subject in so far as my investigation 

 of the presentation-time has afforded figures dealing with 

 the reaction-time also. 



The figures, given hère for the reaction-time might be 

 supposed to be not quite accurate, as in ail experiments 

 the plants were removed to a température of 20° C. before 

 the reaction-time was over. But this really does not make 

 a différence of any importance. At 5° C, 25° C. and 30° C. 

 the reaction-times were found nearly the same, whether 

 the plants remained at thèse températures after the pre- 

 sentation-time was over or were removed to 20° C. 

 Therefore I think thèse figures quite suitable for drawing 

 conclusions about the reaction-time. 



I hâve taken as reaction-time the time elapsing from 

 the beginning of the stimulation till the moment that 50 "/o 

 of the seedlings showedajust perceptible curvation. Thèse 

 values are to be found in the last column of the tables 

 in the appendix. A reaction-time has been mentioned 

 there also in the experiments, where only 40 — 50% of 

 the plants were curved, although in that case there is 

 strictly speaking no reaction-time. In such cases the time 

 elapsing from the beginning of the stimulation till the 

 moment the maximum number was curved has been 

 taken instead of the reaction-time. 



The folhnving table gives a summary of a part of the 

 reaction-times found in this investigation. I did nnt think 



