AN'IESTHET'IC (for derivation, see AN zESTUESIA ) Any remedy used to relieve pain or other hypertesthetie conditions of the sensory nerves. Those that relieve pain alone are fre quently termed analgesics. The broader term is used indiscriminately, including two great groups of anaesthetics: (1) Local anesthetics, affecting a restricted area; (2) general anwsthetics, tem porarily affecting the sensibility of the entire body. Cold is one of the safest local anesthet ics. in the form of cold water or cracked ice. Various freezing mixtures, such as ether spray or ethyl chloride spray, arc even more valuable, but require skill and experience in use, or the part may be frozen and thus injured. Carbolic acid and its allies, creosote, thy/vol. and other volatile oils, containing phenol-like bodies, are powerful anaesthetics. These, when applied local ly. have the power of paralyzing the sense or gans of the skin and mucous membranes. Their use is attended with danger, however, and should be administered by a physician only. The most important of the local amestheties• is cocaine (q.v.), which has the peculiar and useful prop erty of being able to paralyze sensory nerves alone. In a weak solution, it is injected under the skin, which it renders relieving pain, as in neuralgia, and permitting operations on the part. Applied to the mucous membrane, it destroys all feeling, and can be used in the eye, ear, nose, mouth, rectum, vagina, urethra, and bladder, to overcome pain or permit oper ations. Dr. J. Leonard Corning, of New York, in 1885, discovered that when injected in weak solution into the spinal canal, it produced a loss of all sensation below the place of injection. Ex tensive operations have been performed under cocaine, and children have been born without pain to the mother; but there are some serious disadvantages in this medullary narcosis. Eu Caine, holocaine, and orthofo•m have been used for the same purpose as cocaine.
It is probable that for thousands of years the natives of India have used Indian hemp for the relief of pain, while the inhabitants of China have used opium from the poppy plant. In all ages and among all peoples, as far back as his tory records, people have used alcoholic drinks to produce diminished sensibility to pain. Within recent years the pharmaceutical chemist has been industrious in making new compounds to relieve pain. There are scores of such substances now
iu use, among which are acetanilid (q.v.), anti pyrine (q.v.), methacetine, phenacetine (q.v.), thallin, phenetidiu, phenocoll, and salocoll.
In 1800, Sir Humphry Davy, experimenting with nitrous oxide (q.v.) or laughing-gas, sug gested its usefulness as an an:esthetic. In 1844, Dr. Horace Wells (q.v.), an American dentist, demonstrated that the gas may be actually em ployed for painless extraction of teeth. In 1828, Dr. Hickman suggested carbonic acid gas. As early as 1795. Dr. Pearson had used the vapor of sulphuric ether for the relief of spasmodic affections of the respiration. The fact that sul phuric ether could produce insensibility was known to Faraday in 1818, and was shown by the American physicians. Godwin (1822), Mitchell (I832), Jackson (1833), Wood and Bache (1834) ; but it was first used to prevent the pain of an operation by Dr. Crawford W. Long (q.v.), of Georgia, who removed a tu mor from a patient under ether in 1842. ITn fortunately, Long did not publish his discovery to the medical world, and failed to utilize his opportunity. Upon the suggestion of Dr. Jack son. Dr. AV. T. G. Morton (q.v.). a dentist of Boston. after experimenting privately, introduced ether anaesthesia into general use in 1S46. At the request of Dr. John C. Warren, Morton ad ministered ether in an operation at the Massa chusetts General Hospital on October 16, 1846. The fiftieth anniversary of this event was cele brated in Boston on October 16, 1896. In De cember. 1846, Robinson and Liston. in England, operated on patients rendered insensible by the inhalation of ether vapor. This substance was extensively used for a year. when Sir J. Y. Simp son, of Edinburgh. discovered the anesthetic powers of chloroform (see CHLOROFORM) , and introduced the use of it into his own department, midwifery. Since that time, chloroform has been the antesthetie in general use in Europe; but ether is preferred in America, except for chil dren and parturient women. Chloroform should not he given where there is weak action of the heart from disease. No anaesthetic should be given in ease of clironic or severe kidney disease. Consult Probyn-Williams, Guide to Administra tion of A nwsiliet ies (New York. 1901).