418 
POISONOUS EFFECTS OF CARBONIC OXIDE. 
of acetic acid as a solvent for Cantharidine. In the Pharma¬ 
copoeia of 1836, a process was given for the preparation of 
Acetum Cautharidis, in which acetic acid containing 30/8 per 
cent, of real acid was ordered; and he believed when acid of 
that strength was used, the vesicating principle of the 
cantharides was taken up so as to render the preparation 
efficacious; but it happened unfortunately that one of the 
largest makers of acetic acids as supplied for use in pharmacy, 
had misunderstood the intention of the College, and was for 
many years supplying an acid of less strength than that 
ordered, which caused the Acetum Cautharidis when made 
with such acid to be inefficacious. He had some time ago 
fully investigated this subject, and caused the defect alluded 
to to be remedied. 
The Chairman said, he recollected many years ago, when 
the vesicating power of Acetum Cautharidis of the Pharma¬ 
copoeia was found to be deficient, a very efficient and power¬ 
ful preparation was made by substituting glacial acetic acid 
for the acid of the Pharmacopoeia. 
Mr. Attfield stated, that in making some experiments 
with bromacetic acid, he had observed that it acted as a 
powerful vesicant, and he thought it might be worth while to 
try whether it presented advantages over other vesicants. 
THE POISONOUS EFFECTS OF CARBONIC OXIDE. 
By H. Letheby, M.B., M.A., Pli.D., &c. Professor of 
Chemistry and Toxicology in the Medical College of the 
London Hospital. 
A good deal of misapprehension seems to prevail respect¬ 
ing the poisonous action of carbonic oxide. On the one 
hand, accidents have somewhat recently occurred where in 
all probability the effects of the gas were entirely overlooked; 
and on the other, fatal consequences have been unjustly 
attributed to it. Some of this confusion is due to the cir¬ 
cumstance that our standard works on poisons and medical 
jurisprudence, have either omitted the subject entirely, or 
have discussed it in very meagre language. The recent 
catastrophe at the Hartley colliery, and the remarks which 
have been published respecting the supposed influence of the 
gas in causing the death of the men, have created an oppor¬ 
tunity for a re-examination of this question. 
Carbonic oxide w*as discovered by Priestley long before the 
