570 
PHARMACEUTICAL MEETING. 
Oxidum rubrum ; if it gives a process for its production by decomposing nitrate 
of mercury with heat, which serves to distinguish it from the oxide of similar 
composition obtained by precipitation ; and if, together with its characters and 
tests, it states what its composition is in parts by weight,—all the information is 
given that need be given in a Pharmacopoeia, and there will be nothing in what 
is stated that will clash with any received theories, or require alteration to re¬ 
concile it to any system of nomenclature or notation. Its pharmaceutical name 
is red oxide of mercury, and its composition is— 
Mercury . . v . 200 92*6 
Oxygen ... 16 or 7*4 
216 100-0 
In addition to this name, by which alone it should be used in medicine, the 
pharmaceutist may, and indeed should know, that scientific chemists sometimes 
distinguish it as protoxide of mercury, and sometimes as binoxide of mercury, 
names which are inconsistent with each other;* and that it is sometimes repre¬ 
sented by the symbol HgO, and sometimes by Hg0 2 . A chemist in one part 
of the country, or in some particular school, may have been instructed to call it 
protoxide of mercury, while another calls it binoxide of mercury; but all can, 
with equal propriety, and without violating their received and adopted theories, 
employ the name given in the Pharmacopoeia, and no one can gainsay the re¬ 
presentation given of its composition. The name and composition thus assigned 
to it will be good for all time. 
This is the kind of nomenclature that I should like to see generally adopted 
in the Pharmacopoeia, and the changes that have recently been made are quite 
in that direction. There are, however, many names used that are of a different 
description, and which, as we have now become accustomed to their use in medi¬ 
cine, it would perhaps be best to leave unaltered, for unnecessary changes ought 
to be avoided. 
3. Weights and Measures .—Much has been said and written on this subject, 
and many different opinions have been expressed with reference to the weights 
and measures thought to be best suited for use in pharmacy. In actual practice 
the weights used in the British Pharmacopoeia appear to have proved unobjec¬ 
tionable. They are those which alone are used in buying and selling drugs, and 
every druggist is provided with them to every required extent; they are better 
understood, and more familiar than any others to those engaged in making our 
Pharmacopoeia preparations, for which purpose they are fully applicable as 
ordered ; and therefore they appear to be those best suited for use in such opera¬ 
tions. I believe the adoption of the avoirdupois ounce and pound, in place of the 
Troy weights of those denominations, is calculated to promote a more uniform 
and correct preparation of the medicines ordered in the Pharmacopoeia by those 
druggists, of whom there are many, w r ho do not keep complete sets of Troy 
weights beyond the small weights required for dispensing. But, although the 
avoirdupois weights with the Troy grain answer every purpose required for the 
processes of the Pharmacopoeia, it does not follow that they are equally appli¬ 
cable for prescribing and dispensing medicines. For these purposes the apothe¬ 
caries’ weights with their symbols are much better adapted. The grain, 
scruple, and drachm, apothecaries’ weight, are not only well understood, but are 
well suited for indicating the quantities of medicines ordered in prescriptions. 
With reference to this application, the quantities represented by these weights, 
and the relations they bear to each other, are, if not the best that could be de¬ 
vised, at least the best that have yet been introduced or suggested. The symbols 
are also better than any others that have been suggested. They are easily 
written, perfectly characteristic, and readily distinguished, not only from each 
other, but also from other parts of the -writing of a prescription. 
