428 
ON LIQUOR BISMUTHI ET AMMONITE CITRATIS. 
copoeia considered this latter salt to be a harmless constituent of the solution, 
or they would have taken means to exclude it. 
In the advertisements I have referred to, however, it is alleged that the Phar¬ 
macopoeia preparation will contain, in addition to the nitrate of ammonia, “ al¬ 
most invariably arsenic and copper, and frequently antimony,.etc.” These, it is 
stated, will be derived from the impurities notoriously prevalent in metallic 
bismuth. 
It must be admitted that the presence of these metals in varying proportions 
would detract from the value of the Pharmacopoeia solution, and constitute an 
objection to the officinal process. Having prepared several samples of this 
liquor, operating strictly according to the instructions of the Pharmacopoeia, 
I thought it desirable to examine them carefully for these metallic impurities. 
When the liquor was prepared from metallic bismuth purified as the Pharma¬ 
copoeia directs , I failed to detect either copper, arsenic, or antimony. In no 
case could I find the last two metals, but in one case I obtained a trace of copper. 
The liquor which contained it, however, was prepared from metal imperfectly 
purified, for the fusion with nitre was not carried on sufficiently. It is to be 
observed that the Pharmacopoeia directs the commercial bismuth to be twice 
fused with nitre, stirring the molten mixture for a quarter of an hour each 
time. Copper is the most abundant impurity of bismuth, and would most 
readily pass into the liquor prepared from metal containing it. When ordinary 
commercial bismuth is employed for the preparation of the liquor in place of 
the purified bismuth ordered, the resulting solution does undoubtedly contain 
copper, and may contain traces of arsenic and antimony ; although the latter is 
mostly deposited from the nitric acid solution as insoluble antimonic acid, to¬ 
gether with at least part of the arsenic as arseniate of bismuth. 
Judging from the experiments I have made, I think it is safe to conclude 
that when the Pharmacopoeia instructions are properly carried out, the process 
yields with the greatest facility a solution of ammonio-citrate of bismuth which 
is associated only with nitrate of ammonia, and is in other respects pure and 
trustworthy. But the substitution of commercial for purified bismuth would 
be an improper departure from the directions of the Pharmacopoeia, and would 
be likely to cause the introduction of objectionable impurities into the prepa¬ 
ration. The purification of the metal is an important part of the process. 
Although the Pharmacopoeia process is a very satisfactory one, I have found 
it advantageous, in manufacturing this liquor, to depart from the letter of the 
instructions, and to employ, in the place of metallic bismuth and nitric acid, 
the crystallized ternitrate of bismuth, as proposed by Mr. Tichborne some years 
back. This modification of the Pharmacopoeia process, while it is in some 
respects more ready and convenient, happens to afford greater security for the 
purity of the product. It has the additional advantage also of introducing a 
minimum and uniform quantity of nitrate of ammonia into the resulting liquor. 
The crystallized nitrate is readily obtained and easily kept. When bismuth is 
dissolved in nitric acid, the solution, after concentration, deposits well formed 
crystals of the ternitrate. These may be drained on a funnel, and dried by ex¬ 
posure to the air on a porous tile, or on white filter-paper. They are perfectly 
definite in composition, having the formula Bi(N0 3 ) 3 , 5 H 2 0, and they undergo 
no change by keeping. By long exposure to the air they slightly effloresce, 
but that is all. If the salt be prepared from commercial bismuth, a second 
crystallization only is required to render it pure. The preliminary purification 
of the metal may, if desired, be thereby dispensed with. 995 J5 grs. of this salt 
contain 430 grs. of bismuth, and is, therefore, the quantity to be used in lieu of 
the metal and nitric acid ordered by the Pharmacopoeia. 
The process I follow is arranged for a gallon of liquor, and is as follows:— 
