§ 146. Coal-tar-naphtha in its crude state, is an extremely complex liquid, of a most disagreeable smell. Much benzene (C₆H₆) is present with higher homologues of the benzene series. Toluene (C₇H₈), naphthalene (C₁₀H₈), hydrocarbons of the paraffin series, especially hexane (C₆H₁₄), and hydrocarbons of the olefin series, especially pentylene, hexylene, and heptylene (C₅H₁₀, C₆H₁₂ and C₇H₁₄). Besides these, there are nitrogenised bases, such as aniline, picoline, and pyridine; phenols, especially carbolic acid; ammonia, ammonium sulphide, carbon disulphide, and probably other sulphur compounds; acetylene and aceto-nitrile. By distillation and fractional distillation are produced what are technically known ”_once run_” _naphtha_, _90 per cent. benzol_, _50 and 90 per cent. benzol_,[140] _30 per cent. benzol_, _solvent naphtha_, and residue known as “_last runnings_.” [140] Or 50/90 benzol, this indicates that 50 per cent. distils over below 100°; and 40, making in all 90, below 120°. § 147. Taylor[141] records a case in which a boy, aged 12, swallowed about 3 ozs. of naphtha, the kind usually sold for burning in lamps, and died with symptoms of narcotic poisoning. The child, after taking it, ran about in wild delirium, he then sank into a state of collapse, breathing stertorously, and the skin became cold and clammy. On vomiting being excited, he rejected about two tablespoonfuls of the naphtha, and recovered somewhat, but again fell into collapse with great muscular relaxation. The breathing was difficult; there were no convulsions; the eyes were fixed and glassy, the pupils contracted; there was frothing at the mouth. In spite of every effort to save him, he died in less than three hours after taking the poison. The body, examined three days after death, smelt strongly of naphtha, but the _post-mortem_ appearances were in no way peculiar, save that the stomach contained a pint of semi-fluid matter, from which a fluid, having the characteristics of impure benzene, was separated. [141] _Op. cit._, p. 657. § 148. The effects of the vapour of benzene have been studied by Eulenberg in experiments on cats and rabbits, and there are also available observations on men[142] who have been accidentally exposed to its influence. From these sources of information, it is evident that the vapour of benzene has a distinctly narcotic effect, while influencing also in a marked degree the spinal cord. There are, as symptoms, noises in the head, convulsive trembling and twitchings of the muscles, with difficulty of breathing. [142] Dr. Stone, _Med. Gaz._, 1848, vol. xii. p. 1077. DETECTION AND SEPARATION OF BENZENE.