VI.—Other Anæsthetics.
§ 191. When chlorine acts upon marsh-gas, the hydrogen can be displaced atom by atom; and from the original methane (CH4) can be successively obtained chloromethane or methyl chloride (CH3Cl), dichloromethane, or methene dichloride, methylene dichloride (CH2Cl2), trichloromethane, or chloroform (CHCl3), already described, and carbon tetrachloride (CCl4). All these are, more or less, capable of producing anæsthesia; but none of them, save chloroform, are of any toxicological importance.
Methene dichloride, recommended by Sir B. W. Richardson as an anæsthetic, has come somewhat into use. It is a colourless, very volatile liquid, of specific gravity 1·360, and boiling at 41°. It burns with a smoky flame, and dissolves iodine with a brown colour.
§ 192. Pentane (C5H12).—There are three isomers of pentane; that which is used as an anæsthetic is normal pentane, CH3-CH2-CH2-CH2-CH3; its boiling-point is 37-38°. It is one of the constituents of petroleum ether.
Under the name of “Pental” it is used in certain hospitals extensively, for instance, at the Kaiser Friederich’s Children’s Hospital, Berlin.[179] It is stated to have no action on the heart.
[179] Zeit. f. Kinderheilk., Bd. iii.-iv., 1893.
One death[180] has been recorded from its use:—A lad, aged 14, was put under pental for the purpose of having two molars painlessly extracted. He was only a minute or two insensible, and 4-5 grms. of pental was the quantity stated to have been inhaled. The boy spat out after the operation, then suddenly fainted and died. The post-mortem showed œdema of the lungs; the right side of the heart was empty. The organs of the body smelled strongly of pental.