TJNGUENTUM HYDRA It GY It I NITRATIS. 
G4P 
so. (I did not stir it as if I was making an egg cordial, but more in the manner 
one is apt to see in the drawing-room after dinner while enjoying those aromatic 
tipples we so much admire.) I left it and returned in a few minutes, gave it an¬ 
other gentle stir ; the well-known effervescence took place, through which I could 
soon detect the golden tinge. I left it, again returning at short intervals, gave 
it one or two very slight stirs; when the effervescence had subsided, the ointment 
was poured into an 8 lb. dispensing-pot and two smaller ones ; that is now about 
a month ago, and it looks beautiful,—it is rather hard, but not much harder, if 
any, than Unguentum Simplex or Unguentum Zinci, P.B., the consistence of 
which the compilers of the Pharmacopoeia had entirely under their control; nor 
have I ever noticed any change in colour or consistence during use unless 
some of my juvenile coadjutors have distinguished themselves by digging a piece 
out with a steel knife or soiled wooden one ; and I do not consider it is any more, 
if so difficult, to preserve as crystals of nitrate of silver. 
One drachm or so of a clear acid liquor I have noticed occasionally on the 
bottom of the last pot cast, and I have had some fears lest my ointment should 
be acid or irritating; no complaint however has ever been made, and since the 
appearance of the British Pharmacopoeia, and the use of my sense of taste, I have 
been contented on that point, as a comparison of the two formulae will show. 
Mercury 
Nitric Acid 
Lard . . 
Olive Oil , 
London. British. 
2 oz. troy ... 4 oz. avoirdupois 
4 oz. fluid sp.g. 1-42 8oz. fluid sp.g. 1*5 
12 oz.15 oz. 
8 oz. fluid ... 32 oz. 
The British is very much like the form in the Edinburgh Pharmacopoeia. 
I have never operated on large quantities of this ointment, but have been told 
it is much better made on a small scale; if so, there can be no feasible argument 
against it; it is so easily prepared, requires so little attention that it may safely 
rank with decoction of senega or a belladonna plaster, with adhesive margin, as 
one of the slight interruptions one has to submit to in the routine of dispensing 
business. 
With regard to the milder ointment often asked for by the public and pre¬ 
scribed by medical men, the form I like best and always use is one drachm of 
nitrate of mercury ointment and seven drachms of lard, melted together in a small 
porcelain dish and cast into a covered pot; a pot has just been given to me by 
a patient to be refilled, and I find the ointment remaining in it, although diluted 
two months ago, is in a very fair state of preservation ; when a stronger and 
softer ointment is required, almond oil is a very good substitute for the lard, but 
my experience with the latter substance is very limited. I prepared a little this 
morning in the proportions of one part ointment to three parts of almond oil; 
it is liquid at the present temperature, and although it has been mixed eight 
hours is still of a nice yellow colour. 
The proportions of mercury and nitric acid ordered in the London Pharma¬ 
copoeia are, I believe, the same as were originally used in the preparation of this 
ointment, when its reputation as a remedial agent was established ; and we can¬ 
not be too careful, in endeavouring to improve the formulae for established 
remedies, that we do not destroy or lessen their value as a medicine. 
I am, Gentlemen, your obedient servant, 
George Mee. 
8, Torrington Place , Gordon Square , W. C. 
