A NEW SOLVENT FOR EXTRACTING CANTHARIDIN. J^O ^9^Q 
.in. 125 
drained off, to place a heavy diaphragm on the flies, and return the 
solution to the percolator ; after it had passed a second time, a little 
chloroform was added, and finally alcohol .835, until all the first 
menstruum has passed, which is known by the difference in density 
and color of the alcoholic liquid, which contains the brown color 
left by the chloroform. 
By spontaneous evaporation, the dark green chloroform solution 
yielded a crop of crystals of cantharidin, admixed with the green 
fixed oil peculiar to the insect; the whole residue weighed 43 grains. 
After standing 48 hours, that the crystals should have time to sepa- 
rate, the whole was thrown on several thicknesses of filtering pa- 
per to absorb as much as possible of the oil. The crystals were 
then dissolved in a mixture of chloroform and a little alcohol, and 
by spontaneous evaporation were obtained in nearly a pure form. 
The particular merits of chloroform as a menstruum in making 
cantharidin, are, that it is a better solvent than ether or the oils ; 
that a less quantity can be used with more effect, employing alco- 
hol to displace it, and that the cantharidin crystallizes more readi- 
ly from chloroform than from ether. The expensiveness of chloro- 
form precludes its use in the preparation of the ordinary blister- 
ing liquids, or tissues, but where the object is to isolate the can- 
tharidin, the advantages above mentioned, together with the fact 
that most of the chloroform may be regained by distillation, will 
render its use altogether eligible. 
Cantharis vittata. — Not being aware of any chemical exami- 
nation of this insect with a view to demonstrating the existence 
of cantharidin in it, I have applied the solvent property of chloro- 
form to this purpose. One hundred and twenty grains of the flies, 
reduced to powder, were percolated with chloroform, slowly added, 
until three times the weight of the flies had passed, The tincture 
had a greenish brown color, the brown predominating. A few 
drops of this by evaporation on glass, deposited a coating of mi- 
nute crystals visible to the eye, and their shape discoverable with 
a common lens. The whole of the chloroform solution was then 
suffered to evaporate in a suitable vessel, and yielded a residue of 
12 grains. This consisted of crusts of minute crystals admixed 
with a greenish brown fixed oil, the latter in much less quantity 
than the green oil obtained in the same manner from Spanish flies. 
11* 
