The chief use of bismuth is in alloys and solders. The Chromate is employed in calico-printing, and the subnitrate as a paint under the name of pearl-white.
The salts of bismuth also occur in washes for the hair, and pearl-white is used as a cosmetic, but only to a small extent.
§ 815. Medicinal Doses of Bismuth.—The subnitrate and carbonate are prescribed in doses from ·0648 to 1·296 grm. (1 to 20 grains); the valerianate, from ·1296 to ·648 grm. (2 to 10 grains); and the solution, from 1·7 c.c. to 5·2 c.c. (1⁄2 drachm to 11⁄2 drachm).
§ 816. Toxic Effects of Bismuth.—From the researches of Meyer and Steinfeld[892] on animals, it appears that if birds or mammals are poisoned with bismuth salts introduced subcutaneously, or by direct injection, into the veins, death follows in from twenty-four to forty-eight hours, the fatal issue being preceded by convulsions; after death, the colon is intensely blackened, and it may be ulcerated, while the small intestines and the stomach are healthy. If, however, sulphur preparations are given by the mouth, there is then blackening of the stomach, and there may also be ulcers. Meyer is of the opinion that SH2 precipitates bismuth in the parenchyma, and the particles occluding the capillaries thus cause small local necroses; that which escapes precipitation is mainly excreted by the kidneys. Poisonous symptoms in man have been known to occur from the treatment of wounds with bismuth preparations;[893] the symptoms have been somewhat similar to mercurial poisoning; there have been noticed stomatitis with salivation, loosening of the teeth, a black colour of the mucous membrane of the mouth and ulceration, also catarrh of the intestines, and the inflammatory condition of the kidneys usual when that organ has to excrete metallic substances not natural to the body, the “metallniere,” or metal kidney, of the German writers. One case is recorded of death in nine days of an adult after taking 7·7 grms. (2 drms.) of bismuth subnitrate. The recorded symptoms were a metallic taste in the mouth, pain in the throat, vomiting, purging, coldness of the surface, and spasms of the arms and legs. A post-mortem examination showed inflammatory changes in the gullet, windpipe, and throughout the intestinal canal. Recovery has, however, taken place from a single dose three times the amount mentioned. It is possible that the fatal case was due to impure bismuth.
[892] L. Feder-Meyer, Rossbach’s pharmak. Unters., iii., 1882, No. 23; Steinfeld, Wirkung des Wismut. Inaug. Diss., Dorpat, 1884; Arch. exp. P., Bd. xx. 1886.
[893] B. Med. Journal, 1887, i. 749.
§ 817. Extraction and Detection of Bismuth in Animal Matters.—Bismuth appears to be excreted principally by the bowels as sulphide of bismuth; but it has also been detected in the urine, spleen, and liver; and Lubinsky has found it in the saliva and in the epithelium of the mouth of persons taking one of its preparations. Without denying the possibility of its existing in a soluble state in the saliva, its presence in the mouth may, under such circumstances, be ascribed to the lodgment of particles of subnitrate or subcarbonate of bismuth in the interstices of the teeth, &c. It will then be evident that, if a person is supposed to have been poisoned by a large dose of bismuth, and the analyst fail to find it in the stomach, the contents of the bowels should be next examined.
The extraction of bismuth must be undertaken by nitric acid, and boiling for at least two hours may be necessary to dissolve it out from the tissues. Such organs as the liver and spleen are boiled in a finely divided state with a litre of dilute nitric acid (strength, 5 per cent.), for the time mentioned, filtered, and the filtrate evaporated to dryness; the remainder is then carbonised by strong nitric acid; and, finally, the charcoal is boiled with equal parts of nitric acid and water, and the whole evaporated to dryness. By this method every trace of bismuth is extracted. The dry residue may now be brought into solution, and tested for bismuth. The best solvent for the nitrate of bismuth is dilute nitric acid 50 per cent.; the dry residue is therefore dissolved in 100 or 200 c.c. of the acid, and fractional parts taken for examination:—