_Tests._--Heated with caustic potash, it yields chloroform and potassium formate. The chloroform is readily recognized by its odour, and, if the solution be concentrated, by separating as a heavy layer at the bottom of the test-tube. XXXVI.--PETROLEUM AND PARAFFIN-OIL Cases of poisoning by petroleum and paraffin are common, and occur chiefly in children. =Petroleum= is a natural product, and is a mixture of the higher saturated hydrocarbons. The crude petroleum is purified by distillation, and is then free from colour, but retains its peculiar penetrating odour. Different varieties are sold under the names of cymogene, gasolene, naphtha, petrol, and benzoline. Benzoline is highly inflammable, and is often called mineral naphtha, petroleum naphtha, and petroleum spirit. Benzoline is not the same as benzene or benzol, which is one of the products of the dry distillation of coal. From its very general use as a fuel in motor-cars many accidents have happened from inhaling the vapour of petrol. It gives rise to coldness, shallow respiration, syncope, and insensibility, but seldom death. =Paraffin=, also known as kerosene and mineral oil, is a mixture of saturated hydrocarbons obtained by the distillation of shale. By the retailer the terms 'petroleum' and 'paraffin' oil are used indifferently, and each is sold for the other without prejudice. _Symptoms._--These substances are not very active poisons, and, as a rule, even children recover. The breath has the odour of paraffin, the face is pale and cyanotic, hot and dry, and there may be vomiting. Death may result from gastro-enteritis or from coma. _Fatal Dose._--In the case of an adult, 1/2 pint should not prove lethal, and patients have recovered after drinking a pint. _Treatment._--Emetics, purgatives, and stimulants. XXXVII.--ANTIPYRINE, ANTIFEBRIN, PHENACETIN, AND ANILINE Many of the synthetical coal-tar products now so largely employed as analgesics are powerful toxic agents. =Phenazone, Antipyrine, or Analgesin=, is a complex benzene derivative prepared from aniline, aceto-acetic ether, and methyl iodide. It is in colourless, inodorous, scaly crystals, which have a bitter taste. It is soluble in its own weight of water. _Tests._--Can be extracted from an alkaline solution of chloroform. The residue left on the evaporation of chloroform should be employed for testing. If heated with strong nitric acid and allowed to cool, a purple colour is produced. Ferric chloride gives a blood-red coloration, destroyed by the addition of mineral acids. _Treatment._--Stimulants freely, inhalation of oxygen, patient to be kept in the recumbent position. =Acetanilide, Antifebrin, Phenylacetamide= (a constituent of 'Daisy' or 'headache' powders), is obtained by the interaction of acetic acid and aniline. It is in colourless, inodorous, lamellar crystals, which have a slight pungent taste. It is insoluble in water.