NOTES ON THE PHARMACOPEIA. 
395 
in writing and also in printing. There is a greater liability to the introduction 
of errors in this way than there would be if the numbers were expressed in 
words. A few errors which have crept into the British Pharmacopoeia, and 
passed through the press unobserved, appear to have originated in the acciden¬ 
tal substitution of one figure for another. These were noticed in a recent 
number of the ‘ Pharmaceutical Journal,’ and their correction has been autho¬ 
rized by the Medical Council. 
I will now proceed to state the substance of my first report to the Pharma¬ 
copoeia Committee of the Medical Council, dated June, 1868, in which remarks 
and suggestions are made with reference to some of the medicines at present 
described in the Pharmacopoeia, and to others which it may be thought desir¬ 
able hereafter to introduce. 
Acidum Sulphurosum. —The liquid described in the Pharmacopoeia under this 
name, and for the preparation of which a process is given, is a nearly saturated 
solution of sulphurous acid gas in water, but it is difficult to keep this solution 
for any length of time without loss of strength from the escape of some of the 
gas; aud partly from this cause, and partly from the inconvenience attending 
the production of so strong a solution* it is found, as met with in commerce, to 
be of very variable strength. A weaker solution could be kept without so much 
liability to change or variation, and would, 1 .believe, be better suited for 
general use in medicine. Instead of the solution as now ordered, contain¬ 
ing 9-2 per cent, of the acid gas, I would recommend a 5 per cent, solution, 
which could be more easily made, aud the strength of which could be more 
uniformly maintained. 
Besides sulphurous acid in the free state, such as the aqueous solution con¬ 
tains, some of the acid and neutral sulphites are now frequently used in medi¬ 
cine, and might, perhaps, with advantage be introduced into the Pharma¬ 
copoeia. The most important of these are— 
Acid Sulphite of Lime , which is a solution of the very sparingly soluble sul¬ 
phite of lime with excess of sulphurous acid, by which its solubility in water is 
considerably increased ; and 
Neutral Sulphite of Soda, which is freely soluble in water, and from which, by 
contact with any of the stronger mineral acids, sulphurous acid is disengaged. 
Chloroformum. —The extensive use which is made of chloroform as an anaes¬ 
thetic agent, and the danger that may result from its employment in an impure 
state, and especially if contaminated with products resulting from its decompo¬ 
sition, render it very important that the authorized process for its preparation 
should yield it in a state in which it not only is free from impurity when 
recently produced, but will remain so for a considerable time afterwards. A 
statement having been made to the effect that chloroform, prepared according 
to the Pharmacopoeia process, had on several occasions become unfit for use 
within a few weeks after its production, I made a careful investigation of the 
subject, and am fully satisfied that the decomposition alluded to was caused by 
some deviation from the instructions given, and most likely by the use 
of impure sulphuric acid in purifying the crude product. I had several quan-* 
tities of not less than four pounds each, made by the Pharmacopoeia pro¬ 
cess, following rigidly the instructions given, and the resulting chloroform not 
only answered to all the tests, but has remaiued free from any symptoms of de¬ 
composition. One of these samples has been kept now for more than twelve 
months exposed to strong light. On the other hand a sample, in the purifica¬ 
tion of which sulphuric acid not perfectly free from nitric acid was used, began 
to show symptoms of the usual decomposition, in which acid fumes are emitted, 
in a few weeks after it was made. I have found that pure sulphuric acid, with 
the addition of three drops of nitric acid to every fluid ounce, if used in the 
purification of chloroform, will cause this decomposition to take place. Dr-. 
F 2 d 2 
