152 
PECULIARITIES OF PLANTS. 
another, until it has received the pollen from nearly all. In Saxi- 
fraga and Parnassia, the same motion takes place with the stamina. 
The sensitive plant is very remarkable in its motions. The sleeping 
and waking of many plants are remarkable. M. Dutrochet has 
made some experiments by way of ascertaining the cause of so re¬ 
markable a phenomenon. A translation of the same is inserted in 
the Field Naturalist, Vol. 1, page 3, which is as follows :— 
“I took three leaves of the kidney-bean, which 1 shall call A, B, 
C. The leaf A was put into water, and kept during a quarter of an 
hour in vacuo, on restoring it to the air, the air cavities were entirely 
filled with water. The leaf B remained also a quarter of an hour in 
vacuo, but without having been immersed. The leaf C remained in 
its natural state. I put the stalks of these three leaves into vases fil¬ 
led with w r ater, which I exposed to a full strong light. In the even¬ 
ing the leaf A, first exhibited the phenomenon of depressing its leaf¬ 
lets, or of sleep; the leaf B exhibited this phenomenon later; and 
the leaf C later still. 
The next day, the leaf C first presented the phenomenon of 
straightening its leaflets, or of waking; the leaf B next awoke; and 
last of all the leaf A. But the cessation of sleep in the two latter 
was incomplete ; their leaflets remained during the whole day in a 
state of drowsiness, and they made no movement of nutation towards 
the light. The leaf C on the contrary, not only straightened its 
leaflets completely, which constitutes the act of waking, but it incli¬ 
ned the upper side towards the window which admitted the light, 
which constitutes the act of nutation. 
On the evening of the second day, the leaf A was again the first to 
show the phenomenon of sleep; it was followed by the leaf B, and 
lastly by the leaf C : the latter ceased at the same time to keep the 
upper side of its leaf-stalk inclined towards the window; the nutation 
ceased during the night, and the leaflets resumed their natural posi¬ 
tion. 
On the third day, the leaf A presented no symptoms of waking, 
and began to wither, the leaf B revived in a trifling degree, but it 
continued drooping; the leaf C perfectly alive, performed its func¬ 
tions as usual. On the fourth day, the leaf A was dead ; the leaf B 
began to fade, and was dead the next day: the leaf C continued to 
live some time. 
These experiments demonstrate to us, that the sleeping and wa¬ 
king of plants, and their nutation, depend on the air which is con¬ 
tained in their air-organs, and is in proportion even to the quantity 
of that air. 
