ON CANTHARIS VESICATORIA. 
83 
dried in the sun, or in rooms heated by stoves for that pur- 
pose) in nearly air-tight cases lined with paper, to exclude 
as much as possible the atmospheric moisture. 
Properties. 
When exposed to moisture, cantharides speedily undergo 
decomposition, and are thus nearly, if not wholly unfit for 
use. If cantharides have been properly dried and kept in 
well stoppered bottles, they remain unchanged both in ap- 
pearance and in color, and retain their vesicating proper- 
ties unimpaired for a great length of time. A case is upon 
record of their being kept in this manner for thirty years. 
Sometimes, in spite of every precaution to preserve them, 
they will be attacked by a very small worm which preys 
upon and destroys the inner and softer parts of the body, 
while the harder portions remain untouched. It was for a 
long time thought that the part destroyed was totally unpro- 
ductive of vesication, and that the remainder alone contained 
the virtues, but which has been satisfactorily proved to be 
incorrect. Various methods have been devised to destroy 
this insect, viz. by camphor, acetic acid, and by placing the 
bottle containing the infected flies in water, (which must 
be raised to the boiling point,) which destroys both the 
worm and the egg without injuring in the least the 
virtues or the appearance of the flies ; the access of water 
to them must be carefully avoided. The Spanish flies, 
when dried, retain the color and the disagreeable odor to a 
great degree as in the living state. These, when first taken 
into the mouth, have a bitter taste, but upon being chewed 
become exceedingly burning and acrid. The powder is of 
a dark brown, bordering on a grayish color, interspersed 
with numerous shining particles, consisting principally of 
the head, wing cases, and of the legs. The golden red or 
green color should never be considered as a test of 
its superiority, as it is very permanent, scarcely being 
acted upon by boiling water, ether, alcohol, the essential or 
