VEGETABLE PRODUCTS USED BY NORTH AMERICAN INDIANS. 89 
acid with a slight evolution of carbonic acid gas, and this had caused it to be 
condemned as impure, by a customer to whom it had been sent. The quantity 
of carbonate present in it was, however, extremely small. In other respects it 
answered to the Pharmacopoeia tests, excepting that the solution in nitric acid 
gave a precipitate with nitrate of silver indicating the presence of oxychloride. 
This is so frequently met with in commercial subnitrate of bismuth that its de¬ 
tection would not have excited much surprise. Its presence is excused by manu¬ 
facturers on the ground of its making the powder more suitable for some of the 
purposes to which it is applied, so that for such purposes the powder would be 
unsaleable if it did not contain any chloride. The chlorine having been esti¬ 
mated, and the equivalent quantity of oxychloride calculated therefrom, a 
further examination rendered it evident that there was something else present 
besides subnitrate of bismuth. The residue left, after calcination, was in excess 
of that which theory indicated ; and this residue dissolved in nitric acid, mixed 
with dilute acetic acid, and precipitated with sulphuretted hydrogen, gave an 
amount of sulphide much below the theoretical quantity. The cause of these 
discrepancies was found in the filtrate, which yielded an abundant precipitate of 
phosphate of lime. 
While I was engaged in this investigation, my attention was directed to a 
paper in the ‘ Journal de Pharmacie et de Chimie ’ for last March, by Mr. 
Poussin, in which he alludes to the adulteration of subnitrate of bismuth with 
phosphate of lime, and describes a very simple method of detecting it. Mr. 
Poussin says that in one case he found as much as 28 per cent, of phosphate of 
lime in a sample which presented the usual appearance and answered to the 
ordinary tests of subnitrate of bismuth. His process for its detection and es¬ 
timation is as follows :—Dissolve equal quantities of the subnitrate and of tar¬ 
taric acid in nitric acid slightly diluted with water, and add to this a strong 
solution of carbonate of potash until all effervescence has ceased, and the liquid 
is rendered strongly alkaline. “ If the subnitrate of bismuth be pure the liquid 
will be clear, and will remain so even after it has been boiled, but if the sample 
of subnitrate submitted to the test should contain phosphate of lime, even to 
the extent of 1 or 2 per cent., this will form a white precipitate, which will not 
dissolve with long-continued boiling.” 
In applying this test, it is important to observe that the phosphate of lime, 
even when present in large quantity, is not precipitated in the first instance 
after the addition of the carbonate of potash, but its precipitation is immediately 
effected by boiling the solution. From the sample to which I have already 
referred, I obtained in this way 11 per cent, of phosphate of lime, and from 
another sample, which came from a different source, I have more recently ob¬ 
tained no less than 40 per cent, of the same adulterant. 
I have reason to believe that both these samples were of foreign manufacture. 
ON THE VEGETABLE PRODUCTS USED BY THE NORTH¬ 
WEST AMERICAN INDIANS AS FOOD AND MEDICINE, IN 
THE ARTS, AND IN SUPERSTITIOUS RITES. 
BY ROBERT BROWN, F.R.G.S., ETC. 
On ransacking my various journals and notebooks, relating to North-west 
America, I find scattered through them many notices of the economic plants of 
the aborigines of these countries. Though these memoranda can be of but 
little use to civilized art or medicine, yet I have thrown them together as con¬ 
tributions to the economic history of plants and the ethnology of a little-known 
