PREPARATIONS OF THE BRITISH PHARMACOPOEIA. 
401 
uniform formula (omitted, of necessity, only in such cases as aloes, assafoetida, etc.) 
is, “ Macerate for forty-eight hours with three-fourths of the spirit, agitating 
occasionally, then transfer to a percolator, and when the fluid ceases to pass, 
pour into the percolator the remaining fourth of the spirit; afterwards press, 
filter, and make up the original measure of spirit.” Tinct. Aconiti is evidently 
for internal use, the corresponding preparation for external use being Liniment. 
Aconiti. This tincture is about one-fifth or one-sixth of the strength of Flem¬ 
ing’s Tincture, and about one-third of the London. Tinct. Ferri Percliloridi is 
to supersede our time-honoured Tr. Mur. Ferri , and is to be prepared by dis¬ 
solving iron-wire in dilute hydrochloric acid, peroxidizing with nitric acid, 
and evaporating to a syrupy liquid, which is Liquor Ferri Percliloridi , having 
its own place in the Materia Medica. There is some difficulty in the preparation 
of this; care being required in the evaporation to secure complete peroxidation 
of the iron on the one hand, without driving off some of the hydrochloric acid 
on the other. Either error is detected by the tests ; the former by the smell of 
nitrous acid, and the latter by its being not entirely soluble in rectified spirit. 
This liquor, with th?ee volumes of rectified spirit, forms the tincture. Properly 
prepared, it constitutes an elegant tincture, similar in colour and flavour to that 
of the sesquichloride as made under the late formula, but, as w T e must assume, 
superior to it in other respects. Tinct. Gentianx Co. is ordered without the cochi¬ 
neal and with cardamom instead of canella, which changes render it very different 
in colour and flavour from the former. Tinct. Iodi is about one-half the former 
strength, and lias the addition of iodide of potassium, which makes it miscible 
with water, and so more suitable for internal use. Tinct. Limonis is a new tinc¬ 
ture from the fresh peel. Tinct. Lujmli is made from the hop itself and proof- 
spirit, instead of lupuline and rectified spirit, and is a different article, but, I be¬ 
lieve, more generally useful. Tinct. Myrrhx is much stronger, being now one to 
eight, instead of one to eleven and a half. There is an evident wish to secure, 
wherever it is practicable, uniformity in the strength of tinctures,—two and a 
half ounces of the materials to one pint of spirit, or one to eight. This has 
occasioned many of the variations in the new formulas from the old; amongst 
others, in Digitalis, which is now one to eight, and used to be one to ten. Even 
taking into account the altered value of the ounce, this is an important change. 
In the same category we notice Catechu, Calumba, Gentian. Co., Tolu, and 
there are probably others. Tinct. Opii is an ounce and a half to the pint, which, 
taking into account on the one hand the loss of weight in drying the opium 
before it can be reduced to coarse powder as ordered, and on the other hand the 
altered value of the ounce, will leave it much as it was. Tinct. Nucis Vomica; is 
now two ounces to the pint instead of five, w r hich was inconveniently strong. 
Tinct. Rhei has saffron and coriander added, which improve it. Tinct. Senega 
is a new addition, and a very good one. Tinct. Opii Ammoniata is omitted. 
Unguentum Cantharidis is to be prepared according to the Dublin plan, by 
infusion of the flies in oil. This will form an excellent issue ointment, and 
supersede our Unguent. Inf. Canth. We have almond oil instead of olive or¬ 
dered for Unguent. Cetacei and Unguent. Simplex. It can be used unbleached, 
causing only the slightest tinge of colour, which is not objectionable. Unguent. 
Creasoti is three times the former strength. Unguent. Gcillce has a little more 
than half the galls, and Unguent. Gallce et Opii about half the opium, which 
are both changes for the better. We have Unguent. Aconitice , Unguent. Atropice , 
and Unguent. Veratrice , with eight grains respectively to the ounce of Unguent. 
Simplex. The cerates are now properly incorporated with the ointments. 
Vinum Colchici is still ordered to be made from the corms. Surely it should 
have been from the seeds, it is so generally preferred so. Vin. Ipecacuan. is one 
to twenty, instead of one to sixteen. Vinum Opii is an ounce and a half to the 
pint, the same strength as the tincture, and as the opium is to be in rough 
