296 ON THE VOLATILITY AND SOLUBILITY OF CANTHARIDIN. 
through a paper funnel so as not to soil the sides, which was then 
fixed so as to dip half an inch in a mercurial bath having a ther- 
mometer suspended in it. It lost nothing appreciable after being kept 
at 212° F. for half an hour,no sublimate being visible with a lens. 
At 220° F. no visible effect was produced. Kept at 250° F. for 20 
minutes, a very slow sublimation commenced. At 300° F. the vapor- 
ization was but slightly increased. The heat was then raised to 
360° F., when the sublimation became more decided, yet still 
slow. Between 402° F. and 410° F. it fused, and rapidly sub- 
limed at a few degrees higher. Cantharidin at this temperature 
volatilizes with great ease and condenses in beautiful well denned 
crystals like salicylic acid. 
The specific gravity of cantharidin is considerable, as it sinks 
in nitric acid sp. gr. 1*38 ; it is exceedingly acrid ; its powder ap- 
plied to the skin with a little oil, produces speedy vesication, and 
taken internally it is an irritant poison of the most virulent kind. 
Such are some of the more prominent characters of this remark- 
able substance, which exhibits a permanence and want of affinity 
extraordinary in an animal principle. Let us now see how far 
experiments with cantharidin as it exists in the flies in substance, 
correspond with its behavior in an isolated state. 
1st. Is cantharidin, as it exists in Spanish flies, volatile at com- 
mon temperatures, or at the temperature usually employed in 
making the cerate ; and if so to what extent ? 
a. Six hundred grains of powdered cantharides were put into a 
quart flask, a pint of water poured on, and macerated two hours. 
The flask was then adapted to a glass tubulated receiver by means 
of a long glass tube, the joints made tight, and the tube refri- 
gerated throughout its length by a current of cool water, the re- 
ceiver itself being surrounded by water. A sand-bath heat was 
then applied and the materials in the flask kept boiling during 
several hours, until half a pint liquid had distilled. The product 
in the receiver was opalescent, with white particles floating 
through it, and had a strong odor of Spanish flies. It was decanted 
into a bottle, and agitated repeatedly with half an ounce of chlo- 
roform, which d : ssolved the particles and removed the opales- 
cence. The chloroform, when separated with a funnel, and eva- 
porated spontaneously, yielded a colorless semi-crystalline residue, 
having a waxy consistence and a strong odor different from that 
of the flies. It fused at 120° Fahr., was volatile per se, but was 
