30 RESPONSE IN THE LIVING AND NON-LIVING 
in any way explain the reversible nature of these 
responses, when A and B are stimulated alternately. 
These responses are obtained in the plants even when 
completely immersed in water, as in the experimental 
arrangement (fig. 15). It will be seen that in this 
case, where there could be no possibility of shifting of 
contact, or variation of surface, there is still the usual 
current of response. 
I shall describe here a few crucial experiments only, 
in proof of the physiological character of electric 
response. The test applied by physiologists, in order 
to discriminate as to the physiological nature of re- 
sponse, consists in finding out whether the response is 
diminished or abolished by the action of anzesthetics, 
poisons, and excessively high temperature, which are 
known to depress or destroy vitality. 
I shall therefore apply these same tests to plant 
responses. 
Effect of anesthetics and poisons.—Ordinary anes- 
thetics, like chloroform, and poisons, like mercuric 
chloride, are known to produce a profound depression 
or abolish all signs of response in the living tissue. 
For the purpose of experiment, I took two groups of 
stalks, with leaves attached, exactly similar to each 
other in every respect. In order that the leaf-stalks 
might absorb chloroform I dipped their cut ends in 
chloroform-water, a certain amount of which they 
absorbed, the process being helped by the transpira- 
tion from the leaves. The second group of stalks was 
placed simply in water, in order to serve for control 
experiment. The narcotic action of chloroform, finally 
