86 
ON CANTHARIS VESIC ATORIA. 
This opinion has recently been the subject of doubt. Some 
of our most accurate and scientific pharmaceutists have 
been led, as the result of careful experiments, to believe 
that far too much importance has been attached to the de- 
gree of heat that may be safely used in its preparation. 
Without intending to assert a contrary opinion, it is a sub- 
ject of so much importance, that repeated experiments should 
be made, and repeated trials to test the certainty of those 
experiments, where a long established usage is about to be 
changed. The theory that a solution of cantharidin is ef- 
fected by^the higher degree of heat used, which, when com- 
bined with the wax and resin, will form a more active ve- 
sicating ointment, is plausible ; but my own experiments 
have not been attended with that result. After a careful 
trial of this new method of making the cerate, in which its 
activity was decidedly injured, and a similar result having 
occurred in one other instance, I am induced to be- 
lieve that the risk of lessening instead of increasing the ve- 
sicating quality of the ointment is greater than any advan- 
tage that will be likely to result in deviating from the for- 
mula of the U. S. Pharmacopoeia. It is possible that by the 
use of a water bath, and very great care, this injury may 
not occur ; but every apothecary knows that the health, if 
not the life, of a fellow-being may depend upon the efficacy 
of a blister; and that his own reputation, if not that of the 
physician who reposes confidence in his skill, may be inju- 
riously affected by inertness in that among other remedies 
which he is called upon to prepare. He feels, therefore, 
the responsibility that rests upon him, as well in adopting 
any proposed change as in the necessity of insuring cer- 
tainty and uniformity in the strength of this important the- 
rapeutical agent. As expense should not be regarded in 
attaining this object, I will offer the following formula to 
those who may feel inclined to vary from the excellent 
authority of our national Pharmacopoeia. It will be per- 
ceived that it is a combination of the two methods. If any 
