CANTHARIDES 



707 



Constituents. The vesicating principle, CANTHARIDIN, is the 

 lactome or anhydride of cantharidinic acid. It occurs from 0.4 

 to 0.8 per cent, crystallizes in colorless prisms, being without odor 

 and taste, nearly insoluble in water, cold alcohol, carbon disulphide 

 and benzol, and soluble in hot alcohol, chloroform, waxes and fixed 

 and volatile oils. In addition, about 12 per cent of a fixed oil, con- 



FIG. 312. Original package of Spanish Flies (Cantharis) imported from Hungary. 

 After a photograph by Parke, Davis & Co. 



sbting of the glycerides of stearic, palmitic and oleic acid; a resin; 

 and the following organic acids; formic, acetic and uric. The yield 

 of ash is from 6 to 8 per cent. 



Mylabris or Chinese blistering-flies are obtained from Mylabris 

 Cichorii, a coleopterous insect indigenous to the East Indies and 

 China. They are elongated oval or cylindrical (Fig. 311, B), from 

 1.8 to 2.5 cm, in length and from 4 to 11 mm. in breadth, elytra or 



