234 
THE USE OE THE MICROSCOPE AND ITS CRYSTALLO¬ 
GRAPHIC APPLICATION. 
TO THE EDITOR OF THE PHARMACEUTICAL JOURNAL. 
Sir,—Will yon allow me to correct a slight error in your report of the discus¬ 
sion upon Mr. Stoddart’s excellent paper at the Dundee meeting of the Phar¬ 
maceutical Conference ? 
The American work I alluded to in connection with the histology (not solu¬ 
bility) of salts was a very recent publication, viz. Wormley’s 4 Micro-chemistry 
of Poisons,’—a book to which I hope, in an early number of the Journal, to call 
the attention of pharmaceutists in this country,—and not, as reported, my 
friend Mr. Storer’s 4 Dictionary ’ 
The mistake is partly my fault, for the name of the author slipped my memory 
at the moment, and I only alluded to the work in an indefinite way as a 
“ monograph recently published in America.” 
I remain, Sir, truly yours, 
Newcastle-on-Tyne, October 2, 1867. Henry B. Brady. 
BICHLORIDE OF METHYLENE AS A GENERAL 
ANAESTHETIC. 
Dr. B. W. Richardson, whose exceedingly important experiments upon the 
production of anaesthesia have engaged considerable interest throughout the 
medical world for some time past, has brought forward in this department of 
therapeutics, to which he has given so much attention, a new agent for the 
alleviation of suffering. In the first of a course of lectures on “ Experi¬ 
mental and Practical Medicine,” commenced on the 8tli of October, Dr. 
Richardson gave an account of observations upon what is not precisely, as 
he states, a new fluid, but an old one from a new point of view. 
We have long been acquainted with chloroform; and its application in 
producing insensibility to pain has been justly regarded as one of the most 
important services ever rendered to the healing art. More recently we have 
seen, recommended for similar purposes, a compound, closely related to chlo¬ 
roform in chemical constitution and in physiological action. With regard to 
this body, however, the tetrachloride of carbon,* Dr. Richardson puts forth 
a distinct caution. He states, as the result of careful experiment, that both 
on theoretical and practical grounds it is far more dangerous than chloro¬ 
form, and if it were generally used, it would act fatally in a much larger 
number of cases. In its action, it presents the same four stages as chloro¬ 
form, but the second stage is more prolonged and intensified. In one animal 
operated upon, tetanic convulsion of an extreme character was presented 
during this stage. But the worst feature in the administration of this 
body is the slowness of its elimination,—a slowness fully accounted for by its 
high boiling-point. Dr. Richardson therefore directed the steps of this in¬ 
vestigation in the opposite direction, and in July last was rewarded by the 
observation that chloride of methyl is a gentle and certain anaesthetic. Its 
application, however, possesses some practical inconvenience, and it was 
therefore thought probable that a substance might be found intermediate 
between chloride of methyl and chloroform, which should combine the ad¬ 
vantages of both without their disadvantages. The characteristics desired 
are met with in the bichloride of methylene, which obviously stands in the 
* It is assumed in this name that the atomic weight of carbon is 12, and all the symbolic 
formulae in this paper are based on that assumption, the symbols being printed with thick 
type as they are according to the new notation in the Pharmacopoeia. 
