Bismuth forms three classes of compounds in which it is bi-, tri-, and quinqui-valent respectively.

General Sources. - It is found native in the metallic state.

General Reactions. - It is distinguished by the white precipitate which falls on throwing a solution of the nitrate or chloride into water, and the blackening of this by sulphuretted hydrogen (vide p. 713).

General Preparation Of Salts Of Bismuth

Salt

Prepared from

By

Subnitrate, B. and U.S.P.

Bismuth .

Dissolving in nitric acid, throwing the solution into a large quantity of water, collecting and drying the precipitate.

Carbonate, B.P.; Subcarbonate, U.S.P.

Ditto .

Dissolving in nitric acid, evaporating to a small bulk and adding to solution of ammonium carbonate.

Oxide, B.P.

Subnitrate

Boiling with solution of soda.

Citrate, B. and U.S.P.

Ditto

B.P. Dissolving in nitric acid, and adding freshly-made citrate of sodium. U.S.P. Boiling with citric acid and washing with a large quantity of water, when insoluble citrate is formed.

Citrate of bismuth and ammonium, B. and U.S.P.

Citrate of bismuth .

Mixing the citrate to a smooth paste with water and adding ammonia until it is dissolved and the liquid is neutral or faintly alkaline; filtering, evaporating, and drying.

Solution of citrate of bismuth and ammonium, B.P.

Ditto

Do., and diluting instead of evaporating.

General Action. - The soluble salts of bismuth, such as the citrate of bismuth and ammonium, when given in large doses have an action like that of antimony or arsenic and cause gastroenteritis with fatty degeneration of the liver. Small doses of soluble preparations, or larger doses of sparingly soluble preparations, have a sedative effect on the stomach like that of minute doses of arsenic. The subnitrate is so sparingly soluble that its utility in gastric catarrh is probably due to it's mechanical action, like charcoal (p. 542) or binoxide of manganese.

Uses. - Subnitrate of bismuth is used under the name of Spanish or pearl white to whiten the complexion, and as a dusting powder, lotion, or ointment to chapped nipples and hands, abraded surfaces and chronic oozing from the skin, as eczema, in order to take up moisture and allay smarting and itching.

It has also been employed externally as an application in scaly diseases, and in intertrigo in combination with starch and boric or salicylic acid. From its power of diminishing the irritability of mucous membranes it was applied by Ferrier, along with morphine in the form of a snuff,1 to arrest nasal catarrh, and has been used as an injection in ozaena, leucorrhoea, and gonorrhoea, to diminish the irritability. In powder with morphine and starch it is a useful insufflation in laryngeal phthisis and other painful laryngeal affections. It is applied as a local sedative to diminish the pain, nausea, or vomiting in irritable dyspepsia, and to lessen the irritability of the intestine in diarrhoea and dysentery. It is very serviceable, either alone or combined with lime or alkalis in the gastro-intestinal catarrh caused by cold, which is commonly known as cold in the stomach, as well as in the same affection occurring in children at the period of dentition.

1 Bismuth subnitrate 6 drachms; hydrochlorate of morphine 2 grains; powdered acacia 2 drachms.

It is useful in pyrosis, gastralgia, and vomiting, whether the vomiting be from ulcer of the stomach or other causes. It acts remarkably well in the indigestion and pain in the stomach caused by the use of alcohol. In such cases it is best given with a little magnesia, about ten grains of the subnitrate with an equal quantity of magnesia or its carbonate.

The carbonate of bismuth is more soluble in the gastric juice than the subnitrate, and is supposed to be more powerful, and the same advantage, if advantage it be, is possessed by the citrate of bismuth and ammonium. My own experience leads me to prefer the less soluble subnitrate to either of the other preparations.