300 ON THE VOLATILITY AND SOLUBILITY OF CANTHARIDIN. 
hours, numerous minute granular crystals were deposited, which 
gradually increased in amount and size. 
These three experiments prove that hot fatty matter is a good 
solvent for cantharidin as it exists in the flies, and that it retains 
more on cooling than either turpentine or acetic acid. That 
hot oil of turpentine is a good solvent for extracting cantharidin, 
although it does not retain much on cooling, and that officinal acetic 
acid at the temperature of 212° F. will remove cantharidin readily 
from Spanish flies, but retains but a part on cooling. 
d. Five hundred grains of recently powdered flies, contained 
in a flask, were boiled in a pint of water, for an hour, and 
the clear decoction decanted, the residue again treated with 
half a pint of water, so as to remove all matter soluble 
in that liquid. The decoctions w<ere mixed, filtered, and eva- 
porated carefully to dryness. The extract was exhausted by 
repeated treatment with boiling alcohol, which left a dark colored 
pulpy matter, very soluble in water, from which it is precipitated 
by subacetate of lead. The alcoholic solution was now evaporated 
to a syrup, and on cooling yielded a yellow extract like mass, in- 
terspersed with numerous minute four-sided prisms. By washing a 
portion with water, the yellow matter was removed, leaving the 
crystals white and pure. The aqueous washings yielded by eva- 
poration a residue of crystals, and does not vesicate. When 
the alcoholic extract was treated with chloroform the crys- 
tals were dissolved, and the yellow matter left. On evaporating 
the chloroform solution the crystals were re-obtained with all the 
characters of cantharidin. The matter left by chloroform was now 
treated with water, in which it dissolved, except a trace of dark 
substance, and was again evaporated carefully. It afforded a 
yellow honey-like residue, thickly interspersed with crystals and 
strongly acid to litmus, without vesicating power. 
A portion of the yellow matter separated from the alcoholic ex- 
tract by water was boiled with some cantharidin, filtered and 
evaporated. The residue treated with chloroform afforded no can- 
tharidin ; hence it would appear that although the yellow matter 
enables the cantharidin to dissolve in water and cold alcohol, when 
once separated its solvent power ceases. 
Having now studied the effects of the ordinary solvents on 
cantharidin in a free state, and in the condition in which it exists 
