SENSITIVE PLANT. 
297 
cially of the leguminous kind. This is not the case, 
however, with its moving faculty, which from its 
singularity has so long excited the astonishment of 
the naturalist. 
Among those who have attended to its motions 
and the phenomena which result from them, may 
be ranked the learned Dr. Hook. Other naturalists, 
especially Dufay and Duhamel, have, since his time, 
studied the same plant with equal attention ; and 
from their observations we learn that it is difficult 
to touch a leaf of a healthy mimosa, even in the 
most careful and delicate manner, without causing 
it to close. The great nerve which runs along the 
middle of the leaf, serves as a hinge for the sides to 
close upon, and they may be observed to do this 
with great exactness, the two sides being exactly 
opposed to each other. If the pressure is made 
with any degree of force, the opposite leaf of the 
same pair will be affected at the same time, and 
move in the same manner. Upon squeezing the 
leaf still harder, all the leaflets of the same side re- 
sent the affront, and close immediately : the effect 
may be even carried so far that the leaf-stalk will 
approach the branch from which it issues, and the 
whole plant collect itself into a bundle, and become 
reduced to a certain point. 
When the leaves have even faded and turned yel- 
low, or rather when the branches are in a dying 
state, the plant will retain its sensibility, and close 
its leaves upon being agitated. A fine rain will 
not disturb the mimosa in the least ; but if it falls 
