| Per cent. | |||
|---|---|---|---|
| British Pharmacopœia, Switzerland, and Bor. (vj), | 2 | ||
| France, | 10 | ||
| Vauquelin’s | Acid, | 3 | ·3 |
| Scheele’s | „ | 4 to 5 | [234] |
| Riner’s | „ | 10 | |
| Robiquet’s | „ | 50 | |
| Schraeder’s | „ | 1 | ·5 |
| Duflos’ | „ | 9 | |
| Pfaff’s | „ | 10 | |
| Koller’s | „ | 25 | |
[234] Strength very uncertain.
In English commerce, the analyst will scarcely meet with any acid stronger than Scheele’s 5 per cent.
Impure oil of bitter almonds contains hydric cyanide in variable quantity, from 5 per cent. up to 14 per cent. There is an officinal preparation obtained by digesting cherry-laurel leaves in water, and then distilling a certain portion over. This Aqua Lauro-cerasi belongs to the old school of pharmacy, and is of uncertain strength, but varies from ·7 to 1 per cent. of HCN.
§ 253. Poisoning by Prussic Acid.—Irrespective of suicidal or criminal poisoning, accidents from prussic acid may occur—
1. From the use of the cyanides in the arts.
2. From the somewhat extensive distribution of the acid, or rather of prussic-acid producing substances in the vegetable kingdom.
1. In the Arts.—The galvanic silvering[235] and gilding of metals, photography, the colouring of black silks, the manufacture of Berlin blue, the dyeing of woollen cloth, and in a few other manufacturing processes, the alkaline cyanides are used, and not unfrequently fumes of prussic acid developed.