POISON IVY. 25 
acid which bleached vegetable leaves and bits of 
calico in the same vessel, cent no effect on this 
colour. | Mi 
—_—e ether is the proper solvent of this 
juice. A piece of linen spotted with the Rhus 
was immersed in ether and placed over a lamp. 
As soon as the fluid boiled, the spot began to 
grow fainter, and in a few minutes was wholly 
discharged, the ether acquiring from it a dark 
colour. The linen at the same time became 
tinged throughout with a pale —" eS 
acquired from the solution. | 
‘This nigrescent juice, in common with that 
of the Rhus vernix, has, perhaps, claims to be 
considered a distinct proximate — in 
vegetable chemistry. 
The leaves and bark are cntayents to hhe 
taste, which quality appears to be occasioned by 
gallic acid rather than tannin. The infusion and 
decoction become black on the addition of salts 
of iron, but discover hardly ri sabia to 
- gelatin. © | 
A poisonous. eadlies exists in the juice ii 
efiluvium of this plant, like that which is found 
in the Rhus vernix already described. It is said, 
that some other species of Rhus, such as Rhus 
pumilum and Rhus typhinum, possess the same 
4 
