118 
ON ALCOHOLIC TINCTURES* 
30. Cdstoreum. 
1 pt. 
grs. 
15 gr. by 60 gr. 
or 4 pts. alco. at 90° total ext. 
6-00 
a 
75 « 
5 
a 
id. 
a 
6-30 
a 
60 « 
4 
a 
80 
u 
6.60 
a 
75 " 
5 
a 
id. 
<. 
6.50 
u 
75 " 
5 
a 
70 
a 
6.05 
a 
60 " 
4 
tt 
56 
<c 
6-00 
75 " 
5 
a 
id. 
c< 
5.95 
It is very probable that castoreum owes its properties to 
a compound consisting of volatile oil, castorine, and a small 
quantity of resin ; this caused the adoption, in the Codex, 
of alcohol at 80° in the preparation of this tincture (my ex- 
periments confirm me in the use of this alcohol). We see, 
in fact, by the table, that alcohol at 80° the most perfectly 
extracts this substance. I also observed, by evaporating 
these various tinctures, that those prepared with alcohol at 
90° and 80°, remained homogeneous during the evaporation, 
while those prepared with 70° and 56°, immediately sepa- 
rated into two portions; one layer being watery and trans- 
parent, in the midst of which a resinoid mass floated. 
Hence I conclude, that these two alcohols had dissolved a 
smaller quantity of the active principles, and a much greater 
quantity of the albuminous substances. I, therefore, ad- 
here to the degree employed in the Codex, and although 4 
parts of this solvent would be sufficient completely to ex- 
haust this substance, I return, nevertheless, to the general 
rule, adopting the proportion of 5 parts of alcohol, for the 
number of similar cases are too few to require exception. 
31. Cantharides. 
grs. 
1 pt. 15 gr. by 60 gr. or 4 pts. alco. at 56° total ext. 2-22 
" 75 " 5 " id. 2-67 
" 90 " 6 « id. 3-03 
" 75 " 5 " SO 1-12 
" 75 " 5 " 45 3-25 
" 90 " 6 " id. 3-18 
