596 



iVIarvels of the Universe 



Like animals, the Sensitive 

 Plant is powerfull}' affected 

 by anaesthetics of all sorts. 

 If a specimen with its 

 foliage displayed in a nor- 

 mal fashion is exposed to 

 the vapours of chloroform 

 or ether, there is to be seen 

 a gradual drooping of the 

 leaves, for all the world as 

 if the plant had passed into 

 a state of unconsciousness. 

 Electric shocks will agitate 

 the Sensitive Plant to a 

 great extent, and it has 

 been observed that even 

 a thunderstorm will bring 

 about movements on the 

 part of the foliage. 



One very strange phase 

 in the life of the Sensitive 

 Plant is that, like animals, 

 it seems to become " tired " 

 if it is irritated too much, 

 in an undisturbed state. After bciog touchcd Several 



times in fairly rapid succession the leaves fail to respond, and the power of movement is not restored 

 until a period of rest has been allowed. On one occasion it was necessary to take some specimens 

 of this plant by rail. During the early part of the journey the plants showed their disapproval 

 by the collapse of their fohage and general leaf agitation. After a while, however, they seemed 

 to become used to the novel and disturbing conditions, and finally the foliage was displayed in an 

 entirely normal manner. 



Towards the close of the day the Sensitive Plant begins to make preparations for the coming 

 night. One by one the leaflets close together, until an observer feels, with Linnjeus, that the plant 

 must have gone to sleep. It is a wrong idea, however, to associate the evening movements of the 

 Sensitive Plant with the taking of rest. More properly the change in position is to be regarded as 

 a protective measure. In all parts of the world the temperature reaches its lowest point during 

 the hours of darkness, and the leaf-closing of the Sensitive Plant tends to prevent an undue loss 

 of warmth. In the case of specimens which have been forcibly prevented from closing their leaves, 

 the foliage has suffered severely during the night and has been damaged to such an extent that 

 it was of no further use. After all, however, one is bound to admit that there are a good many things 

 in the behaviour of the Sensitive Plant which it is not at all easv to understand. 



I'holo bu'i [.?. Leonard llastin. 



THE SENSIT1\E PLANT. 



Originally a native of North America, this plant has now been naturalized in al! parts 

 of the world. It obtains its name from its immediate perception of the slightest touch, 

 when its leaves close up and the leaf-stallis collapse with a sudden ierli. It is here shown 



THE SURINAM TOAD 



BY R. LYDEIvKER, F.R.S. 



In the article on the Fire-bellied Toad reference is made to the remarkable nursery arrangements 

 which obtain in certain frogs and toads ; and among these none is more peculiar than that char- 

 acteristic of the Tropical South American species commonly known as the Surinam Toad, or some- 

 times, on account of its aquatic habits, as the Surinam Water-Toad. 



