ACTION OF CHL*OROFORM ON THE SENSITIVE PLANT. 75 
plete manner than those of the leaf placed in immediate 
contact with the chloroform. After a rather long time, 
varying according to the vigor of the plant, the leaves open 
again by degrees; bat on trying to irritate them by the 
touch, it is seen that they have become nearly insensible to 
this kind of excitement, and no longer close as before. 
They thus remain as torpid for some time, and generally do 
not recover their primitive sensitiveness till after some 
hours. If, however, when they are in this state of appa- 
rent torpidity, they are subjected again to the action of 
the chloroform, they close again as they did the first time. 
It is not till after they have been chloroformed several 
times, that they lose all kind of sensitiveness, at least until 
the next day; sometimes they even fade completely at the 
end of too frequent repetitions of the experiment. In all 
cases the effects observed are the more marked in propor- 
tion to the purity of the chloroform employed and the 
degree of sensitiveness in the plant. 
An anologous phenomenon is produced if, instead of 
placing the drop of chloroform on the base of the petiole, it 
is laid on the folioles situated at the extremity of a branch, 
the folioles of this branch immediately begin to close pair 
by pair, the common petiole droops, lastly the folioles of the 
other branches close in turn. At the end of two or three 
minutes, the nearest opposite leaf, and if the plant is vigor- 
ous, most of the other r leaves situated below on the same 
stalk, follow their example. When,"after some time, the 
leaves open again, the same want of sensitiveness is mani- 
fested as in the preceding case. 
A singular feature in this phenomenon is the manner in 
which the action of the chloroform is propagated from one 
branch to another, then from one leaf to another, even the 
liquid disappears by evaporation almost as soon as it is de- 
posited. This action, as we have just seen, appears to be 
communicated from the leaf to the stalk, following in the lat- 
ter a descending direction ; generally the leaves situated 
