ATROPA BELLADONNA 681 may be made to reappear by adding more alcoholic solution of potassium hydroxide. Hyoscyamine and hyoscine give this test, but homatropine does not. 2. Gerrard's Test.—If one or two cubic centimetres of a 2 per cent solution of mercuric chloride in 50 per cent alcohol are added to a portion of the residue, a red colour develops immediately. Hyoscyamine produces a yellow colour, which becomes red on warming, while hyoscine (scopolamine) does not produce any changes in colour. 3. Auric chloride gives a citron yellow precipitate to a solution con- taining atropine. If the precipitate be recrystallized from boiling distilled water, and acidified with hydrochloric acid, it will show a minutely crystal- line appearance, and when dry will appear dull and pulverulent. It has a melting point of 137°-139°C. 4. An aqueous solution of hydrobromic acid saturated with bromine produces a yellow amorphous precipitate which, after a short time, forms crystals of various forms, such as spindles, crosses and stars. 5. Physiological Test.—A portion of the purified residue is dissolved in water containing a few drops of sulphuric acid, and one or two drops of this solution are instilled into the eye of a cat. In a few minutes the pupil begins to dilate. Medico-Legal Points.—Poisoning by belladonna occurs accidentally from an overdose of its pharmacopceial preparations or from swallowing " eye drops " in 'mistake. Sometimes, children suffer from poisoning by eating accidentally the berries or seeds, though they are relatively less susceptible than adults. Cases of accidental poisoning have also occurred owing to idiosyncrasy from the external application of belladonna liniment or plaster. Knight Ray son33 reports a case in which poisonous symptoms appeared on the application to the loins of 3 drachms of belladonna liniment. I have seen a case in which a solution of atropine dropped into the eyes to dilate the pupils for retinoscopic examination produced mild symptoms of poisoning. George Heller 14 records a case in which a boy, aged 6 years, suffered from toxic symptoms after two drops of a 1 per cent aqueous solution of atropine sulphate had been dropped into each nostril at 2 p.m. and again at 6 p.m.* in place of a 3 per cent aqueous solution of ephedrine sulphate. An inhabi- tant 15 of Dohad in Gujarat instilled into his ears ear drops containing belladonna. The same night he was seized with severe headache, vomiting and diarrhoea, became unconscious and died. Atropine was detected in the viscera and in the residue of the ear drops. Peter McEwan10 reports a case in which an eye lotion containing atropine was injected by mistake in a man who was about to have a lipoma removed. He developed symptoms of bella- donna poisoning, and his temperature rose to 106°F. Firth and Bentley 17 report three cases of belladonna poisoning resulting from eating the flesh of a rabbit which had been feeding on belladonna leaves. Winder and Manley18 also record the case of a woman, aged 46 years, who suffered from symptoms of belladonna poisoning after she had taken i ounce of the liquid extract of liver as well as 2 drachms of the extract as a remedy for pernicious anaemia. On analysis the liver extract showed ~ the presence of atropine of the strength of 1/25 grain per fluid ounce. She 13. Brit. Med. Jour., April 25, 1908, p. 987. 14. Jour. Amer. Med. Assoc., March 9, 1929, p. 800. 15. Bombay Chem. Analyser's Annual Report, 1927, p. 4. 16. Brit. Med. Jour., Nov. 15, 1947, p. 792. 17. Lancet, Oct. 29, 1921, p. 901. 18. Brit. Med. Jour., Feb. 29, 1936, p. 413.