on the Vegetable Kingdom. 299 



leaves of the plant, some of the leaves shut after a few se- 

 conds. Nay, even when the flask of prussic acid was held out 

 open to a leaf, the leaflets closed almost instantly. In both these 

 cases, the leaves subjected to experiment did not completely 

 regain their primitive sensibility till the end of some hours. 

 It appears also, that even the vapour of the prussic acid 

 exerts an action on the leaves of the sensitive plant. 



DISTILLED LAUREL WATER. 



On the 8th May, at noon, the root of a French bean plant 

 was introduced into laurel water. At the end of some se- 

 conds some of the leaves became crisp at their ends, bending 

 back upon themselves. This state of crispness lasted about 

 half an hour, at the end of which the leaves bent back again, 

 and became quite flabby. In the evening the plant was en- 

 tirely dead. In the repetition of the experiment several 

 times, the crispness of the leaves varied according to circum- 

 stances, and sometimes the plant died without any crispness 

 taking place. 



BELLADONNA. 



On the 9th May, at 9 h A.M. M. Marcet introduced the 

 root of a French bean into a solution of five grains of the 

 aqueous extract of belladonna in an ounce of water. He did 

 not perceive any crispness in the ends of the leaves ; but after 

 some minutes the two lower leaves attached to the stalk 

 changed their position, bending downwards from the top of 

 the leaf stalk. At 9 h P.M. the leaves had reapproached to 

 their natural state, but had become a little flabby. Next 

 morning they resumed their bent down position. In this state 

 they remained twenty-four hours, when the upper leaves had 

 begun to droop. On the 11th, the inferior leaves, which had 

 also changed their position, had begun to become yellow. 

 This yellowness began at the extremities, and gradually ex- 

 tended itself over the greater part of the leaves. On the 13th 

 the plant was entirely dead. 



The belladonna appears to kill plants more slowly than 

 other vegetable poisons ; but it does not act upon them the 

 less distinctly, and often produces very singular effects. Thifc 



