Tests.—Acetate of lead throws down a brown or black precipitate according to the quantity of the gas.
Sewer Gas.—Cesspool emanations usually consist of a mixture of sulphuretted hydrogen, sulphide of ammonium, and nitrogen; but sometimes it is only deoxidized air with an excess of carbonic acid gas.
Symptoms.—If poison concentrated, death may ensue at once; if gas diluted, or exposure only short, insensibility, lividity, hurried respiration, weak pulse, dilated pupils, elevation of temperature to 104°, tonic convulsions not unlike those of tetanus.
Treatment.—Fresh air, oxygen, with artificial respiration. Stimulants, hypodermic of strychnine, and alternate hot and cold douche.
Irritant Gases are—(1) Nitrous acid gas; (2) sulphurous acid gas; (3) hydrochloric acid gas; (4) chlorine; (5) bromine; (6) ammonia. They have the common property of causing irritation and inflammation of the eyes, throat, and air-passages, and may cause spasm of the glottis, bronchitis, and pneumonia.
Sulphurous Acid Gas.—One of the products of combustion of common coal.
Hydrochloric Acid Gas.—Irrespirable when concentrated, and very irritating when diluted. Very destructive to vegetable life.
Chlorine.—Used in bleaching, and as a disinfectant. Greenish-yellow colour, suffocating odour. In poisoning, inhalation of sulphuretted hydrogen gives relief.