PICRIC ACID AND PICRATES. 
§§ 617, 6l8.] 
animal fibres, such as wool; but it can be washed out of plant fibres, 
such as cotton. 
§ 617. Effects of Picric Acid. —Picric acid and its salts have a tend¬ 
ency to decompose the elements of the blood, and to produce methaemo- 
globin ; picric acid is also an exciter of the nervous system, producing 
convulsions. To these two effects must be added a third : in acid solu¬ 
tion it has a strong affinity for albumin, so that if it meets with an acid 
tissue it combines with the tissue, and in this way local necroses are set 
up. The action on albumin is somewhat weakened by the reduction in 
the body of part of the picric acid to picraminic acid, C 6 H 2 (N0 2 ) 2 NH 2 0H, 
a substance that does not so readily form compounds with albuminous 
matters. Doses of 0-5 to 0’9 grm. (about 8 to 14 grains) may be taken 
several days in succession without marked symptoms. Ultimately, how¬ 
ever, what is known as “ picric jaundice ” appears, the conjunctiva and 
the whole skin being stained more or less yellow. The urine, at first ol a 
dark yellow, is later of a red-brown colour. Dyspepsia, with flatulence and 
an inclination to diarrhoea, have been noticed. A single dose of a gramme 
(15-4 grains) caused in a case described by Adler 1 pain in the stomach, 
headache, weakness, diarrhoea, vomiting of yellow matters, quickening 
and afterwards slowing of the pulse ; the skin was of a brown-yellow 
colour, and there were nervous symptoms. The urine was rubv-red. In 
both faeces and urine picric acid could be recognised. The excretion of 
picric acid continued for six days. A microscopical examination of the 
blood showed a diminution of the red blood corpuscles, an increase in 
the white. Cheron 2 has described a case in which the application of 
0-45 grm. (6-9 grains) to the vagina produced yellowness of the skin in 
an hour, and the urine was coloured red. Erythema, somnolence, burning 
and smarting in the stomach and in the kidneys were also noticed. 
§ 618. Tests. —Picric acid is easily separated from either tissues or 
other organic matters. These are acidified with sulphuric acid and then 
treated with 95 per cent, alcohol ; the alcohol is filtered off, distilled, 
and the residue treated with ether ; this last ethereal extract will con¬ 
tain any picric acid that may be present. 
If the ether extract contains much impurity, it may be necessary to 
drive off the ether, and to take up the residue with a little warm water, 
then to cool, filter through a moistened filter-paper, and test the aqueous 
solution. Picric acid, warmed with KCN and KHO, gives a blood-red 
colour, from the production of iso-purpurate of potash. Ammoniacal 
copper sulphate forms with picric acid yellow-green crystals which 
strongly refract the light. If a solution of picric acid be reduced by the 
addition of a hydrochloric acid solution of stannous chloride, the sub¬ 
sequent addition of ferric chloride produces a blue colour, due to the 
formation of amidoimidophenol hydrochloride, C 6 H 2 0H(NH 2 )(NH) 2 HC1. 
1 Wiener med. Woch., 1880 , p. 819 . 2 J. Cheron, Journ. de Ther., 1880 , p. 121 . 
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