308 
ON VESICATING APPLICATIONS. 
applying to the skin a piece of lint wetted with the fluid, and 
covering this with adhesive plaster. I have found the blister- 
ing fluid of Messrs. Pughand Plewsto be of the same strength 
as the Acetum Cantharidis of the College. The specific 
gravity and saturating power of the samples tried were as 
follows; 
SP, GR. ' GRAINS 
Blistering Fluid (P ug h and Plews) 1.06o{«^» 71 
Acet. Canthar. (Bell and Co.) 1.061 f* 72 
Ditto (Herring Brothers) 1.060 " 71 
But this liquid blister, while it may possess advantages in 
some respects, yet is frequently complained of, as uncertain 
and sometimes ineffectual in its operation. The Acetum 
Cantharidis, prepared by houses of the highest standing, and 
who profess strictly to follow the formula of the College, is 
generally found to be deficient of that vesicating power that 
would entitle it to the appellation of a speedy or instantaneous 
blistering application, and hence it often fails to meet the 
expectations of the prescribe^ The physician being thus 
disappointed in the looked-for effect, too often ascribes the 
cause of the failure to the fault of the chemist; and the latter 
is, perhaps, no less disappointed and mortified, on being in- 
formed, when the prescription is next presented at his counter, 
that the blistering application has been directed to be obtained 
from some neighboring chemist, who has gained the physi- 
cian's patronage, by carrying out his intentions more success- 
fully than the formula of the College of Physicians would 
enable him to. This has been effected by preparing the 
Acetum Cantharidis with acetic acid nearly three times the 
strength of that ordered by the College. Beaufoy's Concen- 
trated Pyroligneous Acid corresponds as nearly as possible 
with the " acidum aceticum" of the Pharmacopoeia. The 
specific gravity is 1.048. One hundred grains of this acid 
will saturate eighty-seven grains of crystallized carbonate 
of soda. It consists of 30.8 of anhydrous acid + 69.2 of 
Water- 
