342 
PHARMACEUTICAL MEETING. 
sure employed after simple maceration, as also after maceration and displace¬ 
ment by the Pharmacopoeia process ; also whether, where percolation pure and 
simple was employed, the absorbed menstruum was recovered by pressure or by 
displacement with a similar menstruum or any other,—and all this should be 
performed more than once, and upon an equal quantity in each case, and not 
too small a quantity; for I have not much faith in experiments of this kind 
upon a very small scale. Now, this is a task from which most of us would, 
I fear, shrink. 
Mr. W. Laird, in a paper read at the Conference recently held at Norwich, 
points to the specific gravity of a tincture as a ready means of testing its qua¬ 
lity ; and in the extreme case alluded to by him it was certainly the means of 
showing, as far as the strength of the spirit was concerned, which way the wind 
blew; but for general application many particulars must be considered. 
Should a tincture, for example, have a higher specific gravity than expected, it 
might be thought that the spirit used was too weak; whereas the fact might be 
that the amount of extractive was unusually large, and, vice versa , the spirit 
might be considered stronger than required, while, in reality, the extractive 
was less abundant. Again, the age of a tincture should be considered, as all 
tinctures deposit more or less upon long standing, even after filtration ; r.nd in 
the shop, perhaps I should say pharmacy, where, during the long winter evenings, 
the heat from the gas is great, there is, even with well-stoppered bottles, a certain 
loss of spirit by gradual spontaneous evaporation ; and in the same preparation, 
with the greatest care, the result will not ever be the same, although, as far as 
practicable, the quality of the substances acted upon is so. To more fully illustrate 
this I will give the result of several makings, at different distances of time, of 
one gallon of tincture of opium, made by the old process with the best opium 
dried and powdered : in one case 9 lbs. 4 oz. by weight of tincture, in others 
respectively 9 lbs. 1 oz., 8 lbs. 12 oz., 8 lbs. 13 oz., 8 lbs. 14 oz., 9 lbs. 2 oz., 
and 9 lbs., thus proving, though the difference is not very great, that, with 
every wish to produce a just and good thing, the same result cannot always be 
secured; therefore a certain latitude should be granted, and I should hesitate 
before I condemned a tincture in a general way upon the strength of its specific 
gravity alone. A word or two I may perhaps venture upon with regard to the 
taking of the specific gravity of tinctures. The temperature should have par¬ 
ticular attention, as my own tinctures have, during the month of October, 
varied from 59° to 70° F. in the same situation and hour of the day ; and it may 
be worth remembering that, whereas the London Pharmacopoeia ordered spe¬ 
cific gravities to be taken at a temperature of 62° F., the P. B. directs them to 
be taken at 60° F. ; and this is an advantage, as the specific gravity bottles sold 
by the makers of them in England are and were adjusted or constructed at 
60° F. 
Dr. Walter G. Smith, in an article published in the October number of the 
‘ Pharmaceutical Journal, 1 draws attention to the tinctures of catechu, kino, 
and rhatany, and suggests a mode of distinguishing between the three by a pro¬ 
cess which he admits involves greater difficulties than are apparent at first 
sight, and which will be best understood by those who have made similar 
attempts. Whilst fully acknowledging the value of his suggestions, I do not 
myself think that the result obtained by his mode of proceeding would practi¬ 
cally, and in a general way, be to any extent available. Although it may be 
considered unscientific to say so, I would rather be guided in the estimation of 
a tincture by its generally known characters; I would prefer trusting to the 
senses of sight, taste, and smell, aided perhaps by specific gravity; and to any 
desirous of examining any potable tincture 1 should be inclined to say, with the 
itinerant vendor, taste and try before you buy. 
The object, however, of this paper is not strictly in this direction, but thus 
