ON ALCOHOLIC TINCTURES. 
105 
In this case I was not able to ascertain the quantity of the 
alkaloid it contained. We know, in fact, that impure eme- 
tine is precipitated from its solution by acetate of lead. But 
we know the great solubility of this alkaloid in water, 
which makes its preparation difficult ; on this account they 
have chosen in the Codex alcohol at 56°, for the prepara- 
tion of this tincture. 
This strength of alcohol being that which dissolves the 
greatest quantity of the matter, as we see in the above table, 
I should give it the preference, as well as the proportion 
of 5 parts of this solvent which takes up an excess of matter 
equal to 0-19. 
7. Rhubarb. 
1 pt. 15 gr.by60.gr. or 4pts. alc.at 80°totalext. of tinct 6-00 
a 
75 
a 
5 
it 
id. 
it 
6-34 
a 
60 
66 
4 
a 
56 
66 
6-44 
a 
75 
a 
5 
a 
id. 
66 
6-89 
a 
90 
u 
6 
a 
id. 
66 
6-81 
a 
75 
a 
5 
tc 
45 
66 
6-80 
a 
90 
a 
6 
66 
id. 
66 
6-74 
The two last were extremely mucilaginous. 
I endeavored to discover in which of these tinctures the bit- 
terness would remain, after the addition of water. 10 
grammes of each of these tinctures, prepared with one part 
rhubarb and five of alcohol at 56° and 80°, were diluted 
with the same quantity of water (400 gr.): the tincture with 
the alcohol at 80°, was cloudy, and still rather bitter; that 
prepared with alcohol at 56° remained transparent, and had 
no longer a bitter taste; from which we may conclude that 
alcohol at 80° dissolves more of the active principle. 
But, as we know that this tincture is often administered 
in an undiluted state, in that case alcohol at 80° would be 
far too strong a spirit. I think, therefore, that it would be 
better, on this account, as in the Codex, to adopt alcohol at 
56° only. I should choose the proportion of five parts of 
10 
