July.] FLOWER-GARDEN. 447 
Oft as light clouds o'erspread the summer glade, 
Alarm'd she trembles at the moving shade; 
And feels, alive through all her tender form, 
The whisper'd murmurs of the gath'ring storm; 
Shuts her sweet eye-lids to approaching night; 
And hails with freshen'd charms the rising light." 
« Naturalists," says Dr. Darwin, " have not explained the inm- 
inediate cause of the collapsing of the Sensitive plant; the leaves 
meet and close in the night during the sleep of the plant, or when 
exposed to much cold in the day time, in the same manner as when 
they are affected by external violence, folding their upper surfaces 
together, and in part over each other like scales or tiles; so as to 
expose as little of the upper surface as may be to the air; but do 
not indeed collapse quite so far: for when touched in the night 
during their sleep, they fall still farther; especially when touched 
on the foot-stalks between the stems and the leaflets, which seems 
to be their most sensitive or irritable part. Now as their situation 
after being exposed to external violence resembles their sleep, but 
with a greater degree of collapse, may it not be owing to a numb- 
ness or paralysis consequent to too violent irritation, like the fainting 
of animals from pain or fatigue? A Sensitive plant being kept;^in a 
dark room till some hours after day break, its leaves and leaf-stalks 
•were collapsed as in its most profound sleep, and on exposing it to 
the light, above twenty minutes passed, before the plant was tho- 
roughly awake, and had quite expanded itself. During the night, 
the upper or smoother surfaces of the leaves are appressed toge- 
ther; this would seem to show that the office of this surface of the 
leaf was to expose the fluids of the plant to the light as well as to 
the air." 
The sensibility of this plant is worthy of admiration, that not 
only in the evening, or towards night, but at all hours of the day, 
with the least touch, or concussion of air, the leaves just like a tree 
a dying, droop and complicate themselves immediately, and pres- 
ently after recover, resuming their former position; so that a per- 
son would be induced to think they were really endowed with the 
sense of feeling. 
The cause of this, seemed so hard to be discovered, that a cu- 
rious Malabarian philosopher, upon his observing the nature of this 
plant, without being able to discover the cause of its sensibility, 
ran mad; just as Aristotle is said to have flung himself headlong in- 
to the sea, because he could not comprehend the reason of its 
ebbing and flowing. 
These plants are more or less susceptible of the touch according 
to the warmth of the air in which they grow, being always more 
irritable in proportion to the heat thereof. 
The light is not the only cause of their expansion, nor the dark- 
ness of their contraction, for they are often closed in the afternoon 
two or three hours before the sun descends the horizon; and if the 
frames in which they are kept, be, in the fore part of the day, co- 
vered for hours, so as to render the place completely dark, yet the 
leaves will continue their expansion. 
