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 
recularity of its own. 
My second miseiving 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.—lIn studyine 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 anesthetic agent, vapour of chloroform, 
was blown into the closed chamber containing the plant. 
