PICRIC ACID 475 30 grains as an anthelmintic. It is a powerful antiseptic, but it is chiefly used in the treatment of ankylostomiasis. In large doses thymol acts as a poison and produces a burning sensation in the stomach, nausea, vomiting, diarrhoea, tinnitus, headache, giddiness, collapse and death from respiratory failure. It may cause abortion in a pregnant woman and may colour urine green. Forty grains of thymol killed a woman, 34 years old, in 3 hours and 30 grains taken in two doses of 20 and 10 grains proved fatal to a woman, aged 40 years, on the 9th day,35 while a dose of 300 grains caused only diarrhoea.36 The washing out of the stomach and the administration of the symptomatic treat- ment are the chief remedial measures to be adopted in poisoning by thymol. Avoid alcohol and fats or oils. The post-mortem appearances are irritation of the stomach and intestines, fatty degeneration of the hver and congestion of the lungs. Chemical Tests.—A solution of thymol in chloroform, when warmed with a small piece of caustic potash, assumes a dark-red colour. Thymol dissolved in glacial acetic acid and warmed with an equal amount of strong sulphuric acid yields a violet-red colour, PICRIC ACID (CARBAZOTIC ACID, TRINITROPHENOL, TRINITROPHEN), CoH2(NO2)3OH This is obtained by the action of nitric and sulphuric acids on phenol. It exists as yellow crystalline prisms or plates, and explodes under the action of heat or percus- sion. It is soluble in 90 parts of water, and in about 12 parts of alcohol. It Has no odour, but has an intensely bitter taste, and consequently has been used as a substitute for hops in beer. Picric acid precipitates albumin, and causes local necrosis. It decomposes the red blood corpuscles, and produces methcemoglobin. It also irritates the central nervous system, causing convulsions. Symptoms.—Pain in the stomach ; severe vomiting of yellow matter ; diarrhoea with yellow stools; the conjunctivas and the skin assume a bright yellow colour, which is known as " picric jaundice " ; the pupils are dilated; there may be itching and eczema ; the urine is at first dark yellow in colour, and later becomes ruby red, owing to the formation of picramic acid, but it does not contain bile or albumin; there may be anuria and strangury; rapid pulse; muscular cramps; convulsions; drowsiness; delirium; stupor and collapse. Fatal Dose and Fatal Period.—The fatal dose and fatal period are uncertain. Poisoning has followed thirty grains, but recovery has ensued after swallowing about 300 grains. In his annual report for the year 1943, the Chemical Examiner, Bengal, mentions a case in which death occurred on the 4th day after the ingestion of picric acid. Treatment.—Wash out the stomach. Give diuretics and purgatives. Administer morphine to relieve pain. The antidotes are proteins as found in raw eggs and milk. The administration of large doses of dextrose has been recommended as this substance is believed to aid the reduction of picric acid to the less poisonous picramic acid. Post-mortem Appearances.—All the viscera are stained yellow and are congested. The stomach and the upper part of the intestine show signs of irritation. Chronic Poisoning.—Men who handle picric acid in munition plants and get dusted over with it suffer from dermatitis which may be extremely irritating. Workmen engaged in the manufacture of the explosive, melinite, which chiefly consists of picric acid, suffer from a form of chronic poisoning, the chief symptoms being abdominal cramps, vomit- ing, diarrhoea, loss of appetite and loss of weight. A case37 is recorded in which a youth, aged 17, was unpacking "Explosive D", ammonium picrate, which covered his face and hands and got into his eyes. He suffered from conjunctivitis and tubular nephritis with heavy albumin and casts in urine. Chemical Tests.—An aqueous solution is intensely yellow, is acid to litmus and dyes wool and silk yellow. Ammonio-sulphate of copper produces a green precipitate. When an aqueous solution of picric acid is warmed with potassium cyanide, a blood- red colouration is produced owing to the formation of potassium isopurpurate. Medico-Legal Points.—Picric acid is used as a yellow dye for silk and wool, and is also used in the manufacture of explosives and fireworks. It has produced toxic effects when swallowed in the form of a solution, when applied externally and also when inhaled in the form of dust or fumes. Picric acid is now largely used as a dressing for burns, and one death 3S has been recorded from the poisonous effects thus produced, 35. Barnes, Jour. Amer. Med. Assoc., Sep. 16, 1922, p. 954. 36. Jour. Amer. Med. Assoc^ 1912, Vol. 57, p. 1744. 37. Jour. Amer. Med. Assoc^* Oct. 19, 1929, p. 1243. 38. Alexander, Med. Press and Cir^ 1912, p. 112.