88 
ADULTERATION OF SUBNITRATE OF BISMUTH. 
/ 
moving the more oxidizable metals. It may be conveniently and successfully 
applied to quantities of the metal varying from four ounces to a pound by means 
of a gas furnace. The process, however, is insufficient for the removal of copper 
and silver ; and it is with reference especially to the former of these that the prin¬ 
cipal difficulty is experienced in purifying some of the crude bismuth and bismuth 
ores of commerce. At the present time large quantities of Australian ore, rich 
in copper, are waiting the discovery of a method by which the bismuth it con¬ 
tains may be economically separated in a state of sufficient purity to admit of 
its being used for pharmaceutical purposes. When this question has been satis¬ 
factorily solved, there is every reason to believe that a great reduction in the 
price of the metal will take place. In the mean time we shall have much impure 
bismuth, containing copper, which, although applicable for one of the purposes for 
which bismuth is required,—namely, the preparation of fusible metal,—is not 
well suited for the production of the compounds of bismuth used in medicine. 
Already the attention of metallurgists has been directed to the importance of pro¬ 
viding a supply of purified bismuth for pharmaceutists, and I am assured by 
houses extensively engaged in this branch of metallurgy that bismuth, free from 
arsenic, copper, or any material impurity, may now be obtained by those who 
are willing to pay the price for it.* As this purified bismuth is prepared by men 
accustomed to such operations from the ores which yield it most readily, it will 
be found the most economical and best course for those who require pure bis¬ 
muth to buy the metal in the purified state, or otherwise it will be necessary, 
in applying the process of the Pharmacopoeia, to use crude bismuth which is 
free from copper and silver. 
With reference to Liquor Bismuthi et Ammonia Citratis , on which there 
has been some correspondence in this Journal, it may be stated that, if the 
conditions specified in the Pharmacopoeia be fulfilled, that is to say, if the 
bismuth employed has been purified in the manner described, and if the purified 
metal, and also the solution prepared from it, answer to the tests as given, the 
latter will be free from arsenic , lead , copper , and silver. These are the im¬ 
purities most likely to occur, and to the removal or detection of which the pro¬ 
cess of purification and the tests of the Pharmacopoeia are directed ; but if it 
were the object of a manufacturer to introduce other impurities which would 
elude detection by the tests as given, it would no doubt be possible to do so. 
I have recently met with two instances of such adulteration in subnitrate of 
bismuth, an account'of which will be found in the following article. 
NOTE ON A NEW ADULTERATION OP SUBNITRATE OE 
BISMUTH. 
BY DR. REDWOOD. 
I have recently had occasion to examine two samples of subnitrate of bismuth, 
which have proved to be adulterated to a great extent, by the admixture of a 
substance which none of the tests usually applied would detect. These samples 
were sent for examination by wholesale druggists who had been led to suspect 
that they were not genuine, but who were greatly surprised to learn the extent 
and nature of the adulteration. 
The first of the samples was sent me last May. It presented the usual ap¬ 
pearance of the variety of subnitrate of bismuth generally met with in commerce 
in the form of powder, without any crystalline character. It dissolved in nitric 
* I have recently purchased such at 20s. a pound, the price of crude bismuth being at the 
same time 18s. a pound. 
