Page:The American Cyclopædia (1879) Volume III.djvu/778

768 CARBAZOTIC ACID CARBOLIC ACID nauseating and griping effects. Caraway seed is imported from Europe, and is also supplied Caraway. in part from our own gardens. It is largely cultivated in Essex and Suffolk, England. CARBAZOTIC ACID. See PIOEIO AOID. CARBOLIC ACID (synonymes, carbon oil acid, phenol, phenyl hydrate, phenyl oxyhydrate, phenyl alcohol, phenous acid, phenic acid, phenylic acid, phenylous acid, phenylic alcohol, phenolic acid, phenylated water, spirol, saly- con, coal-tar creosote, and incorrectly creosote and cresylic acid), a chemical substance now largely employed in medicine and the arts. In 1832 Reichenbach discovered among the pro- ducts of the distillation of beech-wood tar a peculiar body to which, on account of its prop- erty of preserving meat from decay, he gave the name of creosote. In 1834 Runge found a similar substance in coal tar, which he named carbolic acid, or carbon oil acid. Immediately there arose a controversy among chemists as to the true constitution of these two bodies. Rei- chenbach, jealous of his fame, maintained that they were identical ; but Laurent in 1841 found carbolic acid to be a different body from creo- sote, and it was he who introduced the new name of phenol, phenic acid, phenylic hydrate (Gr. <j>aiveiv, to light), in allusion to the use of coal gas for illuminating purposes. The con- fusion engendered by these early controversies is still apparent in scientific works, and even Gmelin treats of carbolic acid and creosote as being identical. The difficulties of the case have not been improved by the multiplicity of names which have been given to the com- pounds. For the sake of accuracy and simpli- city, it would have been better if all parties had adhered to Runge's original name of car- bolic acid. Runge wrote in 1834 : " Carbolic acid is a colorless, acid, oily stuff, that sinks under water, and possesses great refracting power. Its odor is empyreumatic, taste highly caustic and burning. It has powerful action on the skin, accompanied by a burning sensa- tion, producing a white stain, which afterward becomes red, and the skin peels off. In this respect it resembles creosote, but it differs from creosote in being decidedly acid, in being pre- cipitated by acetate of lead, and in not being acted upon by ammonia and air, but changed by even dilute nitric acid into a red-brown sub- stance ; it also precipitates gelatine ; all which properties are wanting in creosote. Carbolic acid precipitates albumen as well as gluten, and protects organic matter from decay ; and what is more remarkable, it immediately removes all odor from decaying organic matter, such as meat, when this class of bodies is covered with the liquid acid, and in this property is prefera- ble to chlorine. It is not identical with the principle of smoke, as meat treated with it tastes abominably." In his treatise on ele- mentary chemistry, published in 1847, Runge recommends carbolic acid for the embalming of bodies ; he says : " The carbolic acid of coal tar, discovered by me, is preferable for this purpose to sublimate or any other agent; it has extraordinary action on decaying matter ; for example, stinking fish become entirely ino- dorous in carbolic acid, and after being dried are not again subject to putrefaction." Since the early researches of Runge many new facts have been ascertained in reference to the body discovered by him. Carbolic acid crystallizes at ordinary temperatures in long colorless nee- dles, apparently belonging to the trimetric sys- tem and having a specific gravity of 1'065. The crystals melt at 105 F., while the liquid boils at 369. They are deliquescent, smell like wood-tar creosote, require 25 to 30 parts of water for solution, but dissolve in all propor- tions in alcohol, ether, glycerine, and strong acetic acid. Much of commercial creosote consists solely of carbolic acid. Compounds of carbolic acid with potash, soda, lime, &c., can be obtained ; they are called carbolates, and are quite unstable. It is a volatile sub- stance, and is hence readily diffused through the air. A plumped hide immersed in an aqueous solution of carbolic acid is not tanned, but it is not liable to further putrefaction. India rub- ber is not attacked by carbolic acid, but colo- phonium, copal, and other resins are easily dissolved by it, and remain sticky on drying, which prevents this property of the acid from being employed in the manufacture of varnish. It is a violent poison to plants and animals, and hence must be handled with care. The cases of death from its incautious use are nu- merous. Owing to its antiseptic power, car- bolic acid is a valuable topical application in many surgical cases attended with offensive purulent or other discharges. It was exten- sively tried by Crookes as a prophylactic against the spread of the cattle plague. As it is a vola- tile substance, it possesses the great advantage of being readily diffused through the air. Car- bolic acid paper, which is much used for pack- ing fresh meats, is prepared by melting five parts of stearine at a gentle heat, then thor-