298 
PHARMACEUTICAL MEETING. 
Before the publication of the last London Pharmacopoeia, the only diluted 
acetic acid recognized was the Acetum Destillatum, which was ordered to be pre¬ 
pared by the distillation of “ vinegar,” but it does not state whether the vinegar 
is to be French-wine vinegar or malt vinegar, and if the latter, what strength, 
whether proof or any other. From Mr. Phillips’s notes in the P. L. 1836, I 
presum q proof vinegar is the article intended to be used, and which is estimated 
to contain five per cent, of real acetic acid, a part of which is lost in the process 
of distillation. Hence distilled vinegar must necessarily be of variable strength, 
but is assumed by Mr. Richard Phillips, and I suppose by the College also, to 
contain 4 - 6 per cent, of real acid. 
Hence, in the Pharmacopoeia of 1851, where Acidum Aceticum Dilutum, pre¬ 
pared otherwise than by distillation, is first introduced, the proportion of strong 
acid to water therein ordered is such as to afford a dilute acid of the same strength, 
namely, 4*6. On turning to Paris’s 4 Pharmacologia,’ sixth edition, published in 
1825, under the article Acidum Aceticum Dilutum I find these words :— 44 Mr. 
Phillips states, that when prepared according to the directions of the Pharma¬ 
copoeia it varies (in sp. grav.) from 1007 to 1009 ; and that 1000 grains of the 
latter require for their saturation 145 grs. of subcarbonate of soda. I appre¬ 
hend, however, that it will be found quite impossible to obtain a dilute acetic 
acid equal in strength or specific gravity to that last mentioned, by the process 
of the London College ; it may even be doubted whether it can be produced of 
the specific gravity 1007. The general run of distilled vinegar, as found in the 
shop of the druggist, varies from 1005 to 1006, and contains from 2-80 to 2-826 
per cent, of real acicl; when of the specific gravity 1009 it would contain about 
4-73 per cent. Dr. Powell states ( 4 Translation of the Pharmacopoeia of Lon¬ 
don,’ 1815) that 4 one fluid ounce ought to dissolve at least thirteen grains of 
white marble or, what is equivalent to it, 39-67 grains of crystallized subcar¬ 
bonate of soda ; acid of this strength corresponds very nearly with six degrees 
of the revenue acetometer, the proportions being as follows:—100 grains of Phar¬ 
macopoeia strength will saturate 8-68 grains of crystallized subcarbonate of soda; 
100 grains of acid of 6° of the acetometer will saturate 8*70 grains of the salt.” 
On referring to the acetometer table, I find that 6° is equal to 2-826 of real acid 
per cent., which is nearly two per cent, less than the indication of our present 
Pharmacopoeia. The strength of distilled vinegar of the Edinburgh College is 
three per cent., and the dilute acetic acid of Dublin 3*5 per cent. It would 
therefore appear that the estimation of the strength of distilled vinegar by both 
these colleges is not far from correct, and that the practice of the Dublin College 
in ordering the dilution of the acetic acid of commerce (sp. grav. 1044) to afford 
an acid of 3*5 per cent, is not so far out of the way as to lead to any serious in¬ 
convenience. On the other hand, the assumption of the London College, that 
distilled vinegar contained 4-6 per cent, of real acid, has occasioned an incalcu¬ 
lable amount of inconvenience and confusion, as I*will endeavour to show. 
I believe the first introduction of strong acetic acid into the London Pharma¬ 
copoeia was in 1824, under the name of Acidum Aceticum Fortius, and was very 
nearly the same strength as that obtained by the process of the P. L. 1836, and 
still retained in the materia medica, although no formula is now given, namely, 
30"8 per cent. Why that particular strength was adopted I am not prepared 
to say, except that it is very well adapted for the preparation of Acetum Cantlia- 
ridis, which is a clear and efficient preparation. Previous to the introduction 
into the Pharmacopoeia of this Acidum Aceticum, 30'8, Beaufoy and Co., of 
South Lambeth, had been in the habit, for many years, of preparing acetic acid 
of such strength that one pint of that and seven of water were directed to be 
mixed to produce an acid 44 equal to distilled vinegar used by chemists , apothe¬ 
caries ,” etc. This dilution, I find, affords an acid of about three per cent., the 
same as the distilled vinegar of the Edinburgh Pharmacopoeia. This acid, 
called one to seven, in the preparation of which the greatest care was always 
