EXPERIMENTS ON THE SENSITIVE PLANT. 



359 



Comparative Trials of the Action and Relaxation of Three Sensitive Plants. 



Exps. 



The time. 



The point they fell to. 



The times they 

 took to rise in. 



The point to which they rose. 









No.l. 



No.2. 



No. 3. 



'The 1st and 3rd rose 







J" To the lowest point, 1 



min. 



min. 



min. 



to the highest point, 



1. 



8 o'clock A.M. 



-! and became sta- I 

 |_ tionary. J 



f To the lowest point, 1 



51 



24 



32 



■< the 2n d not so high, 

 and then became 



k stationary. 



/The third rose to the 

 highest point, the 



2. 



9£ A.M. 



< but the second I 

 [ lower down. J 



f The second & third 1 



77 



18 



38 



< 2nd and 1st not so 

 high, and then be- 



\ came stationary. 



1 All three rose to with- 

 in a little of the 



3. 



11 A.M. 



I lower than lowest I 

 [ point. J 



40 



30 



60 



< highest point, and 

 there became sta- 

 l tionary. 



4. 



12 Noon. 



Below lowest point. 



30 



30 



35 



/ All threewithin a little 

 \ of the highest point, 

 f The 2nd and 3rd to 



5. 



40 min. p.m. 



Below lowest point. 



60 



65 



30 



■j highest point, the 

 [ 1st not so high. 





2 p.m. 



f 1st only below low- \ 

 \ est point. J 



45 



45 



45 



Ditto, 

 f 3rd to highest point, 





3 p.m. 



Ditto. 



45 



45 



45 



\ the 1st and 2nd not 



1 so high. 



[ 1st and 2nd to highest 





3ip.M. 



Below lowest point. 



15 



15 



15 



\ point, 3rd not so 

 I high. 



From these experiments we may draw the following conclusions : — 



That there is no fixed time for the leaves of any of the plants to move 

 through its course. 



That they are less affected as they become accustomed to the stimu- 

 lus, but the power of collapsing is increased (although not in the same 

 degree), so that they do not move through the same arc. 



That they require a stronger or quicker stimulus to produce motion 

 after being some time accustomed to it, which was evidently seen in 

 comparing these with others which had not been stimulated. 



It may also be observed that when these plants collapse in the even- 

 ing they have nearly the same quantity of flexion as when roughly 

 touched at noon ; but if touched after they have collapsed from the 

 effect of the evening, they become much more bent than by the same 

 touch at noon. This would seem to arise from a disposition to collapse 

 in the evening, and a power of increasing that disposition and action 

 when stimulated. 



Their collapsing more in the day, and erecting themselves less after 

 a repetition of such actions, may assist in explaining the principle on 

 which this depends. 



