414 Action of Metallic Poison on Vegetation, 



which was used in the experiment is also decomposed in the soil, 

 and there becomes generally insoluble. 



In a word, poisonous metallic substances may be mixed with 

 the soil before sowing, without any fear that the plants which 

 will germinate and vegetate in the soil containing any sensible 

 quantity. 



This conclusion will be found conformable to that of M. de 

 Hemptinne. The author of the second notice, M. Verver, can- 

 didate at the University of Groningue, has mixed with the soil, 

 in various proportions, arsenious acid, bi-arsenite of potash, and 

 sulphate of copper, and afterwards several sorts of farinaceous seeds 

 were sown in the ground thus prepared. He observed, as the 

 preceding author had, that a too great proportion of arsenious acid 

 prevented germination ; that in the opposite case it took place 

 without obstacles, and that the plants offered no traces of the 

 poisonous substances. 



The same resulted from the use of the bi-arsenite of potash. 



The sulphate of copper had no effect in preventing germination, 

 a fact conformable to the experience of the preceding author. 



M. Verver in fact discovered that the salt became insoluble, 

 without doubt from the decomposing influence of the carbonate of 

 lime, in opposition to M. Louyet ; that observer not being able to 

 discover in that case any traces of copper in the vegetables submitted 

 to experiment. 



Little balls of arsenious acid and meal did not prevent vegetation. 



The plants submitted to experiment presented no traces. It was 

 the same when the bi-arsenite of potash in powder, or arsenious 

 acid placed at the root, when young, or of cresses in full vegetation. 

 All these experiments are confirmative, as will be seen, of the pre- 

 ceding ones. Other results were produced when the plants were 

 watered with an arsenical solution. A polygonum orientale in full 

 flower having been watered with a solution of bi-arsenite of potash, 

 perished in twenty-four hours, and the author succeeded in discover- 

 ing clearly the presence of arsenic not only in the leaves and stalks, 

 but also in the seeds of the vegetable. It appears then that metallic 

 poisons can penetrate into the seeds of vegetables, at least under 

 circumstances, of which it was at one time doubtful. 



