208 INORGANIC AGENTS 



69° F., in 25 parts of boiling water which results in forming a saturated solution 

 on cooling which contains about 1.2 per cent, of picric acid. It is readily soluble 

 in chloroform and ether. , 



Action Internal. — ^When given internally picric acid stains the skin, 

 mucous membranes and urine yellow and, in large doses, causes nausea, 

 vomiting and purging, convulsions, hemolysis and death in collapse. It 

 is eliminated as picramic acid. Its use in medicine is chiefly confined to 

 its external action. 



Action External. — Picric acid is a powerful germicide. Ehrenfried 

 found the saturated aqueous solution fifty times more powerful than a 

 one per cent, solution of phenol. While slightly irritating in saturated 

 solution it soon produces a marked analgesic action which is persistent. 



Solutions coagulate albumin and on raw surfaces a scab is quickly 

 formed through coagulated serum. This effect is valuable on clean, fresh 

 wounds and in granulating wounds and ulcers which are free from pus. 



On suppurating surfaces the scab formed may only confine the pus. 

 There is no agent in surgery which stimulates so effectually the process 

 of epidermization or the formation of new skin. Picric acid possesses 

 great osmotic power, solutions permeating rubber gloves. 



Uses External. — Picric acid is commonly employed by dissolving it 

 in the proportion of 3 drams to the quart of boiling water and the result- 

 ing sterile, saturated solution is then ready for use. It has been applied 

 with succeas to sterilize the unbroken skin for operations. Its greatest 

 field of usefulness lies in the treatment of burns of the first and second 

 degree. After cleansing the burns with tincture of green soap and water 

 and lysol solution, and pricking vesicles, strips of sterile gauze soaked 

 in the saturated solution are applied and covered with sterile, absorbent 

 cotton and bandage. On the third day the dressing is removed, after 

 wetting with picric acid solution, and reapplied to remain a week. The 

 same application is useful in fresh lacerated wounds and in ulcers and 

 granulating surfaces, after suppuration has ceased. 



The saturated solution is sometimes used to allay pruritus and as a 

 stimulant in chronic eczema. 



Uses Internal. — The potassium salt — potassium picrate — is occasion- 

 ally administered as an anthelmintic for round and tape worms. Young 

 pigs, gr.iv-viii, (.24-.5); lambs, gr.vii-xx, (.5-1.3). 



AciDUM BoRicuM. Boric Acid. H3BO3. (U. S. & B. P.) 

 Synonym. — Boracic acid, E. ; acide borique crystallis6, Fr.; borsaure, G. 

 Derivation. — Made by evaporation and crystallization of solutions obtained by 

 passing steam issuing from rocks in volcanic regions of Italy, through water; or 

 by the action of hydrochloric or sulphuric acids upon borax. Na^BjO, (borax) -j-lO 

 H2O+2 HCl — 4 H3BO34-2 NaCl-(-5 H^O. Recovered by filtration and Vecrys- 

 tallization. 



Properties. — Transparent, colorless scales, of a somewhat pearly lustre, or, 

 six-sided triclinic crystals, or a light, white, very fine powder, slightly unctuous 

 to the touch; odorless, having a faintly bitterish taste, and permanent in the air. 

 Soluble in 18 parts of water and in 15.3 parts of alcohol; also soluble in *.6 parts 

 of glycerin. It is feebly acid. 



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