566 
LECTURES ON T1IE BRITISH PHARMACOPEIA. 
others who took part in the discussion (Pharm. Journ. vol. xvi. p. 15). It is 
to be hoped, therefore, that the word fresh will be omitted from the formula in 
a future edition. 
Bismuthum Album is the Edinburgh name for the London Bismuth i 
Nitras and the Dublin Bismutld Subnitras. Etymologically, the term white 
bismuth is equally applicable to the carbonate, oxychloride, and nitrate of bismuth 
all three of which are found in commerce. On the other hand, the name bis¬ 
mutld nitras can only refer to one, the officinal one, of these three white powders, 
and as it is a name which need not alter with any new views of the atomic con¬ 
stitution of the salt, is the one which had most claims to retention. 
Calomelas. —See PIydrargyri Ciiloridum. 
Ciiloroformum.— The process given for the preparation of chloroform is 
from the Dublin Pharmacopoeia, with two important improvements in the de¬ 
tails of purification. First, the washed, but still impure chloroform is to be 
agitated with sulphuric acid for five minutes only ; and, second, after agitation 
it is to be rectified from chloride of calcium and slaked lime. Now Dr. Christi- 
son has shown (Pharm. Journ. vol. x. p. 253) that chloroform, if left in contact 
with ordinary sulphuric acid, which contains, as it generally does, an impreg¬ 
nation of nitrous acid, will, in less than twenty-four hours, undergo decompo¬ 
sition and afterwards rapidly evolve chlorine ; and that even with pure acid 
prolonged contact sets up a similar change. Hence the importance of restrict¬ 
ing the period during which the chloroform is to be shaken with the acid, and 
hence the expediency of redistilling from lime as well as chloride of calcium, in¬ 
asmuch as any trace of acid is thereby neutralized and retained in the retort. 
In the tests of the purity of chloroform we have another indication that scientific 
researches on this substance have been consulted. Pure chloroform “ evolves 
no gas when potassium is dropped into it.” This is Hardy’s application (Re- 
pert. de Chem. and Chem. News, vol. v. p. 286) of Heintz’s observation that 
■ chloroform is not attacked by the metals of the alkalies even at the boiling-point. 
If the chloroform contain alcohol of any kind, or other substances susceptible of 
alteration by potassium or sodium, a disengagement of hydrogen or light carbu- 
retted hydrogen and carbonic oxide takes place. 
Collodium.— In explanation of the circumstance, pointed out by Dr. Red¬ 
wood in the first of these lectures, that the process given in the new Pharma¬ 
copoeia for the preparation of the pyroxylin, of which collodium is a solution, 
yields a perfectly insoluble article, it transpires that the formula was allowed to 
be inserted just as received from its author, no allowance being made for the 
alteration in the strength of its nitric acid. We may, of course, expect that 
this omission will be rectified in a future edition. [It has not been corrected in 
the smaller edition recently issued.] 
Decocta. —The remarks of Proctor (Pharm. Journ. 2nd ser. vol. i. p. 10) 
that, in the decoctions, greater uniformity would be obtained by making both 
the time of boiling and the quantity to be ultimately produced definite, seem to 
have been acted on, though Decoctum Quercus and Decoctum Hordei are still 
exceptions to what otherwise is the rule. Not so another remark of the same 
pharmaceutist, that “ Decoctum Aloes Compositum would probably be in no re¬ 
spect injured by the omission of saffron, a costly and nauseous stimulant of 
questionable efficacy.” In Decoctum Sarsse and Decoctum Sa.rsx Compositum , 
the sarsaparilla is directed to be “ not split.” Bell (Pharm. Journ. vol. i. p. 55) 
pointed out the inutility of the protracted bruising and infusing and simmering 
of the root ordered in a previous Pharmacopoeia, and was confirmed by Whipple 
(Pharm. Journ. vol. xiii. p. 641). These suggestions seem to have been adopted; 
it is due however to the compilers of the last Dublin Pharmacopoeia to state that 
several of the improvements in the decoctions are only so in comparison with the 
■old London and Edinburgh Pharmacopoeias, the Dublin work of 1850 having 
