328 ANNUAL OF SCIENTIFIC DISCOVERY. 



and the other plants began to present slight signs of recovery in the 

 same wa} r . Neither of the plants were entirely destroyed. It was 

 interesting to mark the progressive influence of the poison. The first 

 indication of derangement of the healthy functions of the plants was 

 observed in the leaves. These began to wilt and die at their edges and 

 apices, and this death gradually and uniformly advanced on all sides 

 towards the mid-rib and petiole till the whole or nearly the entire leaf 

 was destroyed. It is an interesting fact in physiology, that the plants 

 first exhibited signs of death in the leaves situated on the side in which 

 the incisions were made. The facts naturally deducible from these ex- 

 periments, are : That the effects of the poison of the rattlesnake upon 

 plants and animals, when introduced into their circulation b}^ a wound, 

 are similar. That it requires a much longer time to affect a plant than 

 an animal. [It should be stated, in order to show that animals were 

 readily affected by the poison of the snake, that, a short time previous to 

 its death, a rat bitten by it died in about two hours.] That the effects 

 were invariably exhibited on the part above the wound, and in no case 

 affected the leaves below it. [This was probably owing to the small 

 quantity of the poison introduced in each instance.] That it invariably 

 affected first the leaves on the side of the plant in which the incision 

 was made. That its influence was invariably first rendered visible on 

 the edges and apices of the leaf-blades. 



ABSORPTION OF INORGANIC POISONS BY PLANTS. 



CHEVALLIER has communicated several observations respecting the 

 absorption of mineral substances by plants. Pepper-wort (Lcpodium 

 saiivum) was planted in earth, and watered with an aqueous solution 

 of tartar emetic, blue vitriol, and sugar of lead ; antimony, copper and 

 lead were found respectively in the stalks of the plants, but only copper 

 or lead in the seeds. He found lead in plants grown in a white lead 

 manufactory, and he likewise confirmed the observation that chloride 

 of sodium is absorbed by plants. The action of arsenious acid upon 

 plants has been investigated by Chatin. He states that this acid is, 

 to a certain extent, absorbed by plants, and that, if they are not de- 

 stroyed by the influence of the poison, it is at a later period again 

 ejected by the roots. He has examined the conditions which favor 

 either the action of the poison or its secretion. We mention here only 

 that the action of the poison on the various kinds of plants exhibited 

 a remarkable difference phanorogamia dying earlier than the crypto- 

 garnia, and the dicotyledons sooner than the monocotyledons. Fithol 

 has confirmed the statements of Chatin ; and he has moreover minutely 

 investigated the unequal distribution of the arsenic absorbed through- 

 out the various parts of the plants. He finds that arsenic acid, em- 

 ployed in the same proportion, and in an equal state of dilution, has 

 a more poisonous action on plants than is exhibited by arsenious acid. 

 Licbig^s Report. 



