BICHLORIDE OF MERCURY. See MERociiv.
BISMUTH.—Bismuthum is a whitish gray, hard, though brittle, metal, with melting-point at 2S6.3° C. It is soluble in nitrohydrochloric, nitric. and hot sul phur acids.
It is very commonly contaminated with lead, iron, and copper, together with traces of arsenic, antimony, and tellurium.
In the metallic form bismuth is not used in medicine, but its salts, particu larly if free from contamination, are of great value.
The garlicky odor sometimes produced in the breath of patients taking the salts of bismuth is due to the presence of the metal tellurium. This fact was first noticed by Sir James Simpson, and was established further in 1S75, when spec imens of bismuth containing tellurium as an impurity invariably produced in the breath the peculiar odor referred to.
The salts of bismuth are numerous, but only the most efficient will be men tioned, together with dosage.
Dose. — The subcarbonate is a white, tasteless powder soluble in dilute nitric acid with effervescence. Dose, 5 to 20 grains.
The subnitrate occurs as a white mi crocrystalline powder soluble in acids. Dose, 5 to 20 grains.
Bismuth citrate is a white amorphous powder, odorless and tasteless, and sol uble in solutions of the alkali citrates. Dose, 1 to 5 grains.
The benzoate is a white, tasteless pow der soluble in mineral acids. It contains 27 per cent. of benzoic acid. Dose, 5 to 15 grains.
Bismuth betanaphtholate occurs as a light-brown, insoluble, odorless powder. Dose, 15 to 30 grains.
The salicylate of bismuth is a white, bulky microcrystalline powder soluble in acids and alkalies. Dose, 5 to 20 grains.
The subgallate is well known under the name of dermatol (q. v.). It is without odor, non-irritant, and non poisonous. Dose, 5 to 20 grains.
Physiological Action.—When applied to excoriated or ulcerated surfaces the salts of bismuth, for the most part, exert an astringent and sedative action. The claims that some of the salts of bismuth possess antiseptic properties — the or ganic compounds—have been substanti ated by experimentation and practical observation: salicylate, benzoate, and betanaphtholate.
Contrary to the observations of Morax and von Pfungen, bismuth in large doses possesses the property of decreasing no tably the amount of sulphuric acid in combination among those subjects whose food consisted chiefly of albuminoid sub stances; indican is decreased and at times it disappears. The action of bis
muth is poorly understood; these facts show that intestinal putrefactions dimin ish decidedly, despite that checking of intestinal peristalsis which bismuth ef fects. Desoto (Semaine 111(id., No. 54, '94).
Bismuth naphtholate (bismuth oxide, SO per cent., and betanaphthol, 20 per cent.) decidedly antiseptic. The drug is partly decomposed in the stomach, but the process is completed in the small intestine. R. W. Wilcox (Med. News, July 31, '97).
The action of the salts of bismuth when taken internally in therapeutic doses is much the same as when applied locally.
The salicylate of bismuth causes a slight increase in the elimination of sul phuric ether by the urine. This elim ination is somewhat diminished two or three days after the administration of the drug. Rovighi (Monat. f. prakt. Wasserheil., p. 372, '93).
The subnitrate is a powerful bacteri cide. It is to this action that .it owes those virtues which have been for a long time universally appreciated in gastro intestinal diseases that are the result of morbid fermentation, and in urethritis. It also owes its efficaciousness to the in dependent action of its oxide and its acid. The oxide has the property of saturating the acid supersecretions of the stomach; the acid has the same qualities and un dergoes slow chemical changes in the intestine. From the time it comes in contact with these digestive regions the subnitrate meets with hydrosulphurous emanations, which, although transform ing it into the black sulphide, set a cor responding proportion of nitric acid free. Because of its own acidity, the nitric acid acts directly on the intestinal mu cous membrane as an astringent; but to this topical action its special antiseptic virtues may be added, for, according to Duelaux, the presence of a trace of nitric acid in an organic solution arrests the evolution of a great number of microbes and hastens their destruction. Mean while its bactericidal action does not cease here; from the time that it comes in contact in its intestinal course with fresh hydrosulphurous vapors it is re duced and transformed into nitrous vapors, the special antiseptic action of which, in regard to the bacteria which secrete putrid gases, has been shown by Girard and Pabst.