BISMUTH SALTS.—The soluble salts of bismuth are all too poisonous to be utilised in practical medicine. The insoluble salts, however, arc widely employed as intestinal antiseptics and as anti-fermentatives in affec tions of the stomach and intestines. The salts of bismuth most in use for this purpose are bismuth salicylate, bismuth suhcarbonate, bismuth sub gallate, and bismuth subnitrate. These are used in comparatively large doses (15 grains up), especially the more insoluble ones, such as the sub carbonate and subnitrate. There are a large number of other bismuth compounds known, but those mentioned are the only ones in extensive use.
BITTERS.—Substances which by their action on the nerves of taste increase the sense of appetite and also stimulate the muscular mechanism of the stomach. Most of the bitters of the market are alcoholic drinks, thinly disguised by the addition of some plant bitter. Some of them are as strong as whisky ; most of them are stronger than strong wines. Aromatic and simple bitters are recognised in medicine, the former containing, in addition to the bitter principle, an aromatic volatile oil. Simple bitters are quassia, gentian, chiretta, calumba, and nux vomica, Aromatic bitters are wild cherry, horehound, cascarilla, angostura, serpentaria, chamomile, etc.
BLACK DEATH.—See PLAGUE.
BLACKHEADS.—Small swellings in the skin, due to obstruction of the openings of the sebaceous glands. The most superficial part of the extruding fatty matter dries and turns black (hence blackhead). Actual exudations of sebaceous masses of the glands of the skin take place, and can be brought nut by pressure between two finger-nails or a watch-key, the exuding matter creating the impression of a whitish worm. The sebaceous plugs, which greatly disfigure the skin, often develop simultaneously with an over-production of a glistening tallow of the skin (stearrhea) about the nose, lips, and forehead. By destruction of entire sebaceous glands, they lead to blotches, to the formation of furuncles, and to various eminences of the skin.
The principal preventive is scrupulous cleanliness, frequent bathing, massage, the use of sulphur soaps, and the addition of tar and wax-paste to the soap. Benzine is an excellent and harmless remedy to dissolve the plugs, and serves to facilitate the squeezing (also with a watch-key), and also as a means for the removal of the outflowing skin-fats. Constipated habits should be overcome.