498 ' MEDICAL JURISPRUDENCE Arseniuretted Hydrogen (Arsenic Hydride, Arsine), AsH3.—This is formed by the action of nascent hydrogen on a soluble arsenic compound, and may be liberated during the charging of accumulators from arsenic con- tained in the lead plates or sulphuric acid. It is a colourless, inflammable gas, having a foetid garlicky odour. It burns with a bluish-white flame, forming water and white fumes of arsenious oxide. It acts as a deadly poison, its discoverer Gehlen having been killed on the ninth day after inhaling a small quantity of the pure gas. ORGANIC COMPOUNDS OF ARSENIC The most important organic compounds of arsenic which are used in medicine are cacodylic acid, sodium cacodylate, atoxyl, stovarsol, tryparsa- mide, salvarsan, neosalvarsan, silver salvarsan and sulpharsenobenzene. Cacodylic Acid (Dimethylarsonic Acid), (CH3)2, AsO.OH.—This is a white, crystalline substance, readily soluble in water and in alcohol, and forms salts known as cacodylates, when it unites with metals and organic substances. It contains 54.3 per cent of arsenic. The dose is £ to 2 grains. Sodium Cacodylate (Sodium Dimethylarsonate).—This is a white, odour- less, .deliquescent, crystalline or granular powder, and contains 35 per cent of arsenic. It is soluble in water and in alcohol. The dose is i to 1 grain to be given by mouth, per rectum or hypodermically. When given by mouth or per rectum, it may be decomposed and give rise to toxic symptoms, viz. garlic taste, nausea, pain in the stomach, thirst and renal congestion with albuminuria. Sodium methyl arsonate (Disodium methyl arsonate, Arrhenal or New Cacodyle) is similar in action to sodium cacodylate and is given in doses of \ to 2 grains by mouth or hypodermically. Atoxyl (Sodium para-aminopjienylarsonate).—It is also known as sodium aminarsonate, sodium arsanilate, soamin or arsamin, and is a white, crystalline, inodorous powder with a slightly saline taste. It is soluble in about five parts of water and dissolves freely in hot water with neutral reaction. It is soluble in 125 parts of alcohol (90 per cent) and is easily soluble, when anhydrous, in methyl alcohol. It usually contains about 24 to 25.6 per cent of arsenic. It is a B.P.C. preparation, the dose being f to 3 grains by mouth or hypodermically dissolved in water. It must be used with caution, as it may cause blindness due to optic atrophy. It has even caused death. A man received 2.4 grammes in four hypodermic injections within eight days and died from pulmonary oedema on the second day after the last injection.1 Sodium acetylarsanilate (arsacetin) is synthetized from atoxyl by the introduction of an acetyl radicle, and may be used in the same doses as atoxyl, but it is less poisonous. Stovarsol (3-Acetylamino-4-hydroxyphenyl£i^nic acid).—It is also known as Acetarsol, Acetarsone or Kharophen. It occurs as colourless crystals and contains 27 per cent of arsenic. It is insoluble in cold water, alcohol and dilute acids, but soluble in boiling water and in alkalies. The dose is 1 to 4 grains. Tryparsamide (Sodium n-phenylglycineamide p-arsonate).—It is a white, crystalline powder and contains 25.1 to 25.5 per cent of arsenic. It is soluble in water, but almost insoluble in alcohol, in ether and in chloroform. The dose is 15 to 30 grains subcutaneously, intramuscularly or intravenously. Salvarsan (Dioxy-diamino arseno-benzene Di-hydrochloride, Arseno- benzoi, 606 ", Kharsivan or Arsphenamine).—It is a pale yellow, crystalline, odourless powder, slowly dissolving in water with acid reaction. It is 1. Munch, Med. Wchnschr., 1909, 56, p. 972.