44 
In a letter to his friend Mutis, he says, “ I have raised a very 
wonderful plant this year in iny Garden. It is a new species of 
Hedysarum from Bengal. This plant has a spontaneous motion 
in its foliage, which seems almost voluntary. You are aware 
that various parts of the vegetable body, especially those sub- 
servient to impregnation, can be so stimulated by the touch as to 
exhibit some kind of movement. You know also the motion of 
some kinds of Mimosa and Oxalis, as well as of the Dionaea mus- 
cipula, arising from the touch of any extraneous body, or from the 
agitation of the wind. But the plant in question is not affected 
by either of these causes. Whether in the open air or in a close 
room, it spontaneously moves its leaflets, now one way, now an- 
other, one, two, or more at a time; not all at once, nor all in one 
direction; and this takes place whether the air be serene, cloudy, 
or rainy. It has not yet flowered, but I expect that event in the 
course of the autumn. The plant requires great heat.” Instan- 
ces of incomprehensible action like this can but awaken the atten- 
tion of the most apathetic. We will give a figure and particu- 
lars of this plant in the fifth page of the Floral Register. The 
irritability of some plants is better known, especially that of mi- 
mosa pudica, or humble plant, whose leaves shrink from the 
touch, the culture of which may be recommended to the curious 
amongst our young friends. Seeds are easily obtained, and an 
efficient hotbed during summer, in which the plants should be 
constantly kept, will sufficiently mature them for the purpose of 
shewing their sensitive peculiarities. This is a property which 
advances the vegetable towards the animal kingdom, just as in- 
stinct advances the brute towards the human species. 
82 Noxious Animals TO Destroy. A novel and scientific me- 
thod of destroying rats, mice, and other animals, appears in Dr. 
Thomson’s Records of Science, from the French of M. Thenard. 
It is by sulphuretted hydrogen gas. Animals, when allowed to 
breathe this gas in a state of purity, fall down as if struck with a 
bullet; and even in a highly diluted state it is peculiarly delete- 
rious ; so much so that a dog is speedily killed by breathing air 
which has been impregnated with a thousandth part only of the 
gas. 31. Thenard states the success of actual experiments ; and 
from these there appears great probability that in old buildings, 
ricks and underground runs of rats, or other animals, the method 
may be advantageously employed. It is easily effected by 
