ARSENIC 499 hygroscopic, and decomposes readily "by exposure to the air. It is soluble in glycerin, and dissolves in three parts of methyl alcohol, but is insoluble in ether. It contains not less than 30 per cent or more than 34 per cent of arsenic. The dose by intravenous injection is 0.1 to 0.6 Gm. or 14 to 10 grains. Neosalvarsan (Sodium dihydroxydiamino arsenobenzene Methanesul- phonate, "914", Neokharsivan, Novarsenobenzene, Novarsenobillon, Neo- arsphenamine or Neoarsphenamina B.P.).—It is a yellow powder, readily dissolving in water with neutral or slightly alkaline reaction. It readily changes in the air, becoming highly poisonous. It is, therefore, supplied in sealed glass ampoules. It contains about 20 per cent of arsenic. The dose by intravenous injection is 0.15 to 0.6 Gm. or 2J to 10 grains. Silver Arsphenamine (Silver Salvarsan, Arsphenamina Argentica).— This is a sodium salt of Silver diamino-dihydroxyarsenobenzene. It is a dark brown powder, readily soluble in water with alkaline reaction. It contains 18 to 21 per cent of arsenic and 12 to 13 per cent of silver. The dose by intravenous injection is 0.1 to 0.6 Gm. or li to 10 grains in a 1 per cent solution. Stdpiharspthenamine (Disodium dihydroxy-diamino-arsenobenzene-di- methylene sulphonate), Sulfarsenol, Kharsulphan, or Sulpharsenohenzene.— It is a yellow powder, dissolving readily in water, and contains about 20 per cent of arsenic. It is a pharmacopceial preparation, and is administered subcutaneously or intramuscularly in doses of 0.1 to 0.6 Gm. or 1J to 10 grains. Mapharsen (Mapharside, Oxophenarsine Hydrochloride or Oxophenar- sinse Hydrochloridum).—It is an odourless, white or nearly white powder, and dissolves in water, in solutions of alkali hydroxides and carbonates and in dilute mineral acids. It contains 29.5 to 32 per cent of trivalent arsenic and 30 to 32 per cent of total arsenic. It is a pharmacopceial preparation and is administered intravenously in doses of J to 1 grain. Oxophenarsine Tartrate or Oxophenarsinse Tartras.—It is an odourless, white or nearly white powder, soluble in 25 parts of water and-in alcohol. It contains 19 to 19.6 per cent of trivalent arsenic and not more than 19.6 per cent of total arsenic. The dose is f to 1J grains intravenously. PROPRIETARY ARTICLES CONTAINING ARSENIC 1. Rough on Rats.—A greyish powder consisting of white arsenic and barium carbonate. Strength, 98.89 per cent of arsenious oxide. 2. Fly Papers.—Strength varying from half a grain to one grain of arsenious oxide per each paper. 3. Weed-Killer.—This consists of a strong solution of caustic soda and arsenite of sodium. Strength, 14rto 40 per cent of arsenious oxide. Eureka weed-killer is a pink powder, containing 60 per cent of arsenic. 4. Fly-Water.—This consists of one part of arsenite of sodium or potas- sium two parts of sugar and twenty parts of water. It is used for killing flies. Paper dipped in this solution and dried is also used for this purpose. 5. Fly-Powder,—This is a mixture of metallic arsenic and arsenious oxide. It contains from 4 to 11 per cent of arsenious oxide. 6. Sheep-Dip.—This is used to destroy parasites in wool. It is sold in packets in the form of a yellow granular powder containing about 20 per cent of arsenious oxide. It is prepared by mixing arsenious oxide and potassium. or sodium carbonate with soft soap and ground sulphur. It is made iesto a solution by mixing it with tar water.