298 Mr F. Marcet on the Action of Minerals 



acting on the nervous system. The first, according to M. 

 Orfila, acts specially on the brain, and the mix vomica on the 

 spinal marrow. 



SEEDS OY THE COCUI.US MENISPERMIS. 



A French bean plant was introduced by the root into a 

 vessel containing a solution of ten grains of the aqueous ex- 

 tract of the seeds of the Coculus menisperviis in two ounces of 

 water. In a few seconds, the ends of two leaves nearest the 

 stalk became slightly crisp, and the extremity of each curl- 

 ed up on the upper surface of the leaf. 



After some hours, the Jeaves nearest the lower part of the 

 stalk changed their position, so as to bend downwards from the 

 top of the leaf stalk. The leaves grew stiff in this position, 

 and remained so for some hours. At the end of a certain 

 time they began to become flabby ; and at the end of twenty- 

 four hours, the plant was quite dead, all the leaf stalks being 

 bent in the middle, and all the leaves withered. 



PRUSSIC ACID. 



Exp. 1. On the 12th May, at 8 h A.M. the root of a 

 French bean plant was put into prussic acid. The leaves did 

 not become crisp, as with some of the preceding poisons, but 

 the leaf stalks began to bend at the middle, and the leaves to 

 hang down at the end of two or three hours, as in the case of 

 opium. At the end of twelve hours the plant was dead, and 

 all the leaf stalks were as if they had been crushed and bent 

 downwards by the middle. 



Exp. 2. One or two drops of concentrated prussic acid were 

 poured on the extremity of a branch of the sensitive plant, 

 (M imosa pudicti) to which some leaves were attached. After 

 some seconds all the leaves closed. It sometimes happened, 

 however, that all the little leaflets of each leaf were not 

 dead, but only those which were nearest the extremity of the 

 branch on which the prussic acid had been poured. The leaves 

 opened again at the end of a quarter of an hour, but they had 

 lost the greatest portion of their sensibility, which they did 

 not recover till after some hours. 



When the prussic acid was held in a dish a little below the 



