ON THE VOLATILITY AND SOLUBILITY OF CANTHARIDIN. 295 
dissolves cantharidin with great readiness, and ranks next to 
chloroform in this regard. The solution deposits the substance in 
crystals by evaporation. The commercial methylic alcohol or 
wood naphtha also dissolves cantharidin, but to a much less ex- 
tent than acetone. When acetic acid sp. gr. 1-41 (U. S. P.) is 
added to cantharidin, it but slightly acts on it in the cold; heat 
much increases its solvent power, which is lost on cooling and the 
substance deposited by standing, though not immediately. One 
part of cantharidin was mixed with 40 parts of crystallizable 
acetic acid and agitated together during five hours, but a small 
percentage was dissolved; but on applying heat the crystals were 
dissolved quickly. On standing, nearly all of the cantharidin 
was slowly deposited in regular crystals. To ascertain whether, 
as has been asserted,* a combination was effected, and an acetate 
of cantharidin produced, an acetic solution of cantharidin was 
evaporated to dryness and the crystals mixed with strong sulphuric 
acid and heated till dissolved, while the nose was held near, with- 
out the slightest evidence of acetic odor ; one-twentieth of a grain 
of acetate of potassa was then added, which instantly evolved 
the well marked smell of acetic acid. Formic acid dissolves but 
a trace of cantharidin cold or hot ; and muriatic acid sp. gr. 1*18 
hardly can be said to act on it in the cold, but when boiling a 
minute portion is taken up. The same is true of phosphoric 
acid dissolved in five parts water. Sulphuric acid sp. gr. 1*840, 
when heated readily dissolves pure cantharidin without being 
discolored, and deposits it in crystals unchanged by cooling. Hot 
nitric acid sp. gr. 138, dissolves cantharidin readily, and deposits 
the greater part of it on cooling in brilliant crystals, unchanged. 
A concentrated solution of ammonia slowly dissolves cantharidin 
to a small extent, and yields it up on evaporation in crystals. 
Solutions of potassa and of soda also dissolve this principle. 
Its Volatility. — About ten grains of pure and perfectly dry can- 
tharidin was spread on the pan of an Oertling's balance, (sensitive 
to l-150th of a grain,) and the equilibrium carefully adjusted with 
platina weights. After exposure for a week to the action of the air, 
a vessel of lime being present to keep the air dry, no change in 
the adjustment had occurred. To further test the volatility of 
cantharidin, a portion of it was put at the bottom of a dry test tube, 
* New York Jour. Pharm. vol. i. p. 72. 
