482 MEDICAL JURISPRUDENCE The oesophageal stricture should be dilated by means of a bougie, or it may be necessary to perform cesophagostomy or gastrostomy. In poisoning by ammonia vapour give oxygen inhalation, or keep the patient in an atmosphere rendered moist with steam. Anodynes may be given for pain. Post-mortem Appearances.—These indicate marks of corrosion, but not so well-marked, as in poisoning by mineral acids. The mucous1 membrane of the mouth, throat, gullet, stomach and duodenum is softened, exfoliated and inflamed in patches of chocolate or black colour. The contents of the stomach are turbid, usually blood-stained, but frequently coffee-coloured. Perforation of the stomach is rare, but may occur in ammonia poisoning. The deeper tissues are inflamed and congested. The mucous membrane of the larynx and trachea shows the same appearances as are found in the mouth, throat, etc. In protracted cases of poisoning stenosis is found more often at the lower end of the oesophagus than at the pylorus. In the case61 of a man who died from poisoning by a solution of ammonia, the viscera were found in a highly congested state, including the oesophagus, the lungs and the pancreas, which latter was adherent to the duodenum, and the contents of the stomach smelled strongly of ammonia and had a soapy feel. The Chemical Analyser detected both free and combined ammonia in the viscera. Chemical Analysis.—The contents of the stomach are alkaline in reaction and soapy to the feel. Ammonia may be separated from organic mixtures by distillation, and other alkalies may be separated by dialysis or by incinerat- ing them in a porcelain capsule to drive off animal and vegetable matter, The residual ash is then dissolved in acidulated water, and tested for the presence of sodium and potassium as given in the following table : — Reagents. Ammonium. Potassium. Sodium. 1. Caustic potash Ammonia gas is given off known Nil. Nil. and heat. by its odour, by its turning red litmus paper blue and by giving rise to white fumes of ammonium chloride when a glass rod wet with hydrochloric acid is brought into contact with it. 2. Nessler's re-agent. Yellow, or brown colouration or Nil. Nil. dark brown precipitate. 3* Tartaric acid Nil. White granular preci- Nil. (strong) and pitate. alcohol. 4. Platinic chloride. Yellow, crystalline precipitate in Yellow, crystalline pre- Nil. solutions acidulated with hydro- cipitate in solutions chloric acid, soluble in 80 per acidulated with cent alcohol. hydrochloric acid, in- soluble in 80 per cent alcohol. 5. Flame test. Nil. Violet. Yellow. The caustic alkalies give a "brown precipitate with silver nitrate; while their carbonates give a whitish-yellow precipitate and effervesce on the addition of an acid. 61. Bombay Chemical Analyser's Annual Report^ 1929, p. 5.