244 
PREPARATION OF VALERIANATE OF ZINC. 
fourth of the distillate was returned to the still, as it 
contained considerable volatile oil — after which the process 
was continued until the distilled water ceased to redden 
litmus paper. 
The product of the distillation is then placed in a porce- 
lain dish, or better, in a large matrass, and an excess of 
hydrated carbonate of zinc (which is ascertained to be free 
from iron) is added. The mixture is allowed to digest at 
a temperature of 190 degrees, Fahr., during two or three 
hours on a sand bath, until saturated. The liquor is then 
filtered and evaporated over a naked fire till reduced to 50 
parts (oz.), when it is placed on plates and the evapora- 
tion allowed to proceed gradually to dryness in a drying 
room, or by any other means at a moderate temperature. 
By this process M. Lefort obtained at three different ope- 
rations, 17, 18, and 1 Si parts of valerianate of zinc from 
1000 parts of valerian root, a much larger yield than any 
process before tried has afforded. 
It is desirable, in operating on valerian root, that it should 
be as freshl y dried as possible, because the acid and oil are sen- 
sibly diminished in quantity by age. It is probable, how- 
ever, that the relative amount, of valerianic acid is greater 
in old than in the recent root, owing to the action of the air 
on the oil. 
I have never been able to obtain more than 35 grains of 
valerianate of zinc from a pound of the root by the ordi- 
nary method of saturating the distilled water, whilst this pro- 
cess yields 126 grains, nearly four times as much. This 
difference is no doubt due in part to M. Lefort's valerian 
being fresher, but chiefly to his new method of manipulat- 
ing. 
There is a distilled water of valerian officinal in the French 
Codex, which is made by distilling one part of valerian with 
six parts of water, until four parts are obtained. This 
water, by standing, becomes more medicinal and perma- 
nent, and there is little doubt that it contains the chief vir- 
