142 
Selected Articles, 
except when aided by heat ; the solution in the latter case isf 
of the colour of dark brandy ; on the addition of water to 
this solution, the cantharidine is precipitated in small acicular 
crystals. Nitric acid, with the assistance of heat, dissolves 
it without change of colour. The solution, on cooling, de- 
posits crystals of the some form, but of a larger size than 
those from the sulphuric acid. Hydrochloric acid acts like 
the nitric. 
A solution of caustic potash dissolves cantharidine. If 
acetic acid be added to this, the cantharidine is precipitated 
in a crystalline state. A solution of caustic soda acts in the 
same manner. Liquid ammonia has no action. 
Oil of turpentine, when boiling, dissolves cantharidine, and 
on cooling deposits it in a crystalline state. Almond and 
olive oils dissolve it with the assistance of heat, but it again 
separates on cooling. Axunge acts in the same way. 
From the analysis of M. M. Pelletier and Henry, can- 
tforidine is composed of 
It may be said, that when cantharides are mixed in olive 
oil or axunge, these substances become charged with the 
vesicating principle, and thus form very active ointments! 
This is true. Cold alcohol dissolves only a very small quan- 
tity of pure cantharidine ; and yet I prefer it as a vehicle for 
its extraction ; but when cantharides are treated with alco- 
hol, this acts at the same time on the cantharidine and the 
green oil with which it is combined in the insect. 
To prepare an ointment with cantharidine, this must be di- 
vided by adding a small quantity of rectified alcohol, mixing 
this with a little axunge, triturating for a long time, and fi- 
nally incorporating it with the rest of the grease. One grain 
of cantharidine to the ounce of axunge forms a very active 
ointment. 
Two kilogrammes of cantharides treated as above xlescrib- 
Carbon 
Hydrogen 
68.56 
8.43 
9.89 
Nitrogen 
Oxygen 
13.15—100.03. 
