PLANT RESPONSE 73 



after which their sensitiveness rapidly declined. Later, 

 being obliged to seek for other specimens, I came upon 

 radish, which gave good results in the early part of 

 November ; but the setting-in of the frost had a pre- 

 judicial effect on its responsiveness. Less perfect than 

 these, but still serviceable, are the leaf-stalks of turnip 

 and cauliflower. In these the successive responses as a 

 whole may be regarded as regular, though a curious 

 alternation is sometimes noticed, which, however, has a 

 regularity of its own. 



My second misgiving was as to whether the action 

 of reagents would be sufficiently rapid to display itself 

 within the time limit of a photographic record. This 

 would of course depend in turn upon the rapidity with 

 which the tissues of the plant could absorb the reagent 

 and be affected by it. It was a surprise to me to find 

 that, with good specimens, the effect was manifested in 

 the course of so short a time as a minute or so. 



Effect of chloroform. In studying the effect of 

 chemical reagents in plants, the method is precisely 

 similar to that employed with nerve ; that is to say, 

 where vapour of chloroform is used, it is blown into 

 the plant chamber. In cases of liquid reagents, they 

 are applied on the points of contact A and B and their 

 close neighbourhood. The mode of experiment was 

 (1) to obtain a series of normal responses to uniform 

 stimuli, applied at regular intervals of time, say 

 one minute, the record being taken the while on a 

 photographic plate. (2) Without interrupting this 

 procedure, the anassthetic agent, vapour of chloroform, 

 was blown into the closed chamber containing the plant. 



