194 ORIGINAL COMMUNICATIONS. 
(no insignificant quantity) is retained by the powder, and 
though saturated equally with the liquid collected, is aban- 
doned and lost. Sometimes the deficiency is made up with a 
new portion of wine ? which will reduce the tincture one-half 
in strength. By displacement, the whole of this might be 
obtained. All that is necessary would be to pour over the 
dregs, on the filter, about two ounces of wine, and the place of 
this, when absorbed, to be supplied by additions of water,, 
until the pint of menstruum is made up from the percolation. 
The same remarks apply to tinctures from the leaves which 
largely absorb the liquids. 
In displacing one liquid by another of a different nature, 
especially alcohol by water, to prevent admixture, it is neces- 
sary to interpose one or two ounces of the same liquid before 
adding another. In most cases, it is preferable to use the 
same menstruum to the end of the process. 
Without any previous maceration, we formed tinctures from 
the leaves of all the narcotic class of plants, some of the 
diuretic class, and likewise from the following substances, viz: — 
Senna, Lobelia, R hat any, Opium, Capsicum, Cubebs, 
Valerian, Rhubarb, Bark, Colocynth, Serpentaria, Helle- 
bore, Ginger, and Galls. 
This method answers equally well for the tinctures of 
animal substances, as Castor, Musk, and Cantharides. 
TINCTURES OP GUM RESINS. 
One of the best results of the displacement application is the 
the beautiful limpid tinctures, obtained from resinous sub- 
stances, in a very expeditious manner. The resinous tinc- 
tures, made by us in this manner, were those of Myrrh, Guai- 
acum, Benzoin, and Assafcetida. 
The coarsely bruised ingredients should be mixed with 
about half their weight of sand before being placed in the in- 
strument, in the neck of which some clean straw should be 
closely pressed; then disseminate rectified alcohol by small 
quantities at the time over its surface. The first portions 
which pass will be turbid, and should be returned back until the 
