EFFECTS ON HEALTH.—Industrial ammonia poisoning is rare. It occurs most frequently in gas works and occasionally in its use, especially the manufacture of ammonium salts. Those engaged in subliming ammonium carbonate incur special risk, but often it is not the ammonia vapour so much as the escaping evil-smelling gases containing carbon bisulphide and cyanogen compounds which are the source of trouble. Occasionally in the production of ice through leakage or by the breaking of carboys of ammonia accidental poisoning has occurred. Some cases are cited from recent literature: A worker was rendered unconscious and drowned in an ammonia water well.[1] Two workers were poisoned (one fatally) in the concentration of gas liquor. Three workers were gassed (one fatally) in the preparation of ammonium sulphate in a gas works. Probably as the result of excessive steam pressure gas water was driven over with the ammonia into the sulphuric acid vessel.[2] Eulenberg[3] reports the occurrence of sulphuretted hydrogen gas poisoning in the production of ammonium salts. The workers succumbed as though shot, although work was being carried on in the open air. They recovered when removed from the poisonous atmosphere. In a large room of a chemical factory phosphoric acid was being saturated with ammonia gas water in an iron lead-lined vessel. Carbonic acid gas and hydrogen gas were evolved, but not to such extent as to be noticeable in the large room. A worker not employed in the room had to do something close to the vessel, and inhaled some of the fumes given off. A few yards from the vessel he was found lying unconscious, and although removed into the open air failed to respond to the efforts at artificial respiration.[4] Lewin, in an opinion delivered to the Imperial Insurance Office, describes poisoning in a man who during two days had been employed repairing two ammonia retorts in a chemical factory. On the evening of the second day he suffered from severe symptoms of catarrh, from which he died five days later. Lewin considered the case to be one of acute ammonia poisoning.[5] Ammonia is frequently used in _fulling_ cloth, the fumes of which collect on the surface after addition of sulphuric acid to the settling vats. This is especially liable to occur on a Monday, owing to the standing of the factory over the Sunday, so that entrance into the vats without suitable precautions is strictly forbidden. Despite this, a worker did go in to fetch out something that had fallen in, becoming immediately unconscious. A rescuer succumbed also and lost his life. The first worker recovered, but was for long incapacitated by paralytic symptoms. Cases of poisoning in _ice factories_ and refrigerator rooms from defective apparatus are reported. Acute and chronic poisoning among sewer men are due mainly to sulphuretted hydrogen gas and only partly to ammonia. The more ammonia and the less sulphuretted hydrogen sewer gases contain the less poisonous are they.