142 poisons: their effects and detection. [§§ i53 _i 55- 
§ 153. Taylor 1 2 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. 
§ 154. 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 
who have been accidentally exposed to its influence. From these sources of informa¬ 
tion, 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. 
DETECTION AND SEPARATION OF BENZENE. 
§ 155. Benzene is separated from liquids by distillation, and may be recognised 
by its odour, and by the properties described at p. 140. The best process of identifica¬ 
tion, perhaps, is to purify and convert it into nitro-benzene, and then into aniline, in 
the following manner :— 
1. Purification. —The liquid is agitated with a solution of caustic soda ; this 
dissolves out of the benzene any bodies of an acid character, such as phenol, etc. The 
purified liquid should again be distilled, collecting that portion of the distillate which 
passes over between 80° and 120 ° ; directly the thermometer attains nearly the 120°, 
the distillation should be stopped. The distillate, which contains all the benzene 
present, is next shaken with concentrated sulphuric acid in the cold ; this will dis¬ 
solve out all the hydrocarbons of the ethylene and.acetylene series. On removing 
the layer of benzene from the acid, it must be again shaken up with dilute soda, so 
as to remove any trace of acid. The benzene is, by this rather complicated series of 
operations, obtained in a very fair state of purity, and may be converted into nitro¬ 
benzene, as follows 
2. Conversion into Nitro-Benzene. —The oily liquid is placed in a flask, and 
treated with four times its volume of fuming nitric acid. The flask must be furnished 
with an upright condenser; a vigorous action mostly takes place without the 
application of heat, but if this does not occur, the flask may be warmed for a few 
minutes. 
After the conversion is over, the liquid, while still warm, must be transferred 
into a burette furnished with a glass tap, or to a separating funnel, and all, except 
the top layer, run into cold water ; if benzene was originally present, either oily 
drops of nitro-benzene will fall, or if the benzene was only in small quantity, a fine 
precipitate will gradually settle down to the bottom of the vessel, and a distinct 
bitter-almond smell be observed ; but if there be no benzene in the original liquid, 
and, consequently, no nitro-benzene formed, no such appearance will be observed. 
3. Conversion into Aniline. —The nitro-benzene may itself be identified by 
collecting it on a wet filter, dissolving it off the filter by alcohol, acidifying the 
alcoholic solution by hydrochloric acid, and then boiling it for some time with 
metallic zinc. In this way aniline is formed by reduction. On neutralising and 
diluting the liquid, and cautiously adding a little clear solution of bleaching-powder, 
a blue or purple colour passing to brown is in a little time produced. 
1 Op. cit., p. 657. 
2 Dr Stone, Med. Gaz., vol. xii. p. 1077, 1848. 
