on the Vegetable Kingdom. 295 



diameter. The cut penetrated to the pith. Into the cut he 

 inserted fifteen or twenty grains of oxide of arsenic, diluted 

 with some drops of water. The cut was then tied up with 

 twigs of osier. On the 8th June, the leaves of the tree began 

 to close, and to curl up at the extremity. On the 15th, the 

 leaves were withered, and the branches had begun to dry. 

 On the 28th, the branches were dry, and in the second week 

 of July, the whole of the stem was quite dry, and the tree 

 completely dead. Another lilac-tree, with a similar cut, but 

 without poison, suffered no injury. This lilac had another 

 trunk or stem, which joined it a little above the ground. This 

 trunk also became dry, about fifteen days after the other, 

 having presented the same appearances. 



When arsenic was introduced below the bark of another 

 lilac, the principal branches of the tree nearest the wound 

 were quite dry at the end of 15 days; but the leaves of the 

 other branches did not fade till the ordinary period. 



MERCURY. 



Exp. 1. — On the 5th of May two or three French bean 

 plants which grew in a pot were watered with about two oun- 

 ces of water, holding in solution twelve grains of muriate of 

 mercury. Next day the leaves drooped, and the stems were of 

 a yellowish brown colour. The watering being continued on 

 the 6th, the stalks were quite yellow on the 7th, and the 

 leaves withered and dry. 



Exp. 2. — On the 3d April, a branch of a rose tree, with 

 two or three rose-buds half developed, had its extremity in- 

 troduced into a flask containing a solution of six grains of 

 muriate of mercury in an ounce of water. On the 5th 

 April, specks of a yellowish brown colour appeared along 

 the ribs of the leaves ; the external petals faded, but the flower 

 notwithstanding seemed to be a little blown. Twenty-four 

 grains of the liquid were absorbed. On the 6th, the streaks 

 were larger, and of a deeper colour, and the leaves very un- 

 healthy. On the 7th, the streaks covered the whole leaf, ex- 

 cept the margin, and the branch was quite dry. The inter- 

 nal petals were not withered, but seemed to have become of a 

 deep colour. 



