Macht called attention to the fact that it is not necessary to have complex chemical compound containing nitrogen in its molecule to produce local anesthesia. He showed that the simple aromatic compound, benzyl alcohol, exhibited marked local anesthetic properties when studied by different pharmacological methods. During a pharmacological study of 23 isomeric octyl alcohols, Macht and Schroeder discovered that these straight chain alcohols all produced marked local anesthesia and, furthermore, that combinations of these acted synergistically. These findings suggested an inquiry into the possible local anesthetic properties of other aliphatic alcohols. In connection with a study of 18 primary aliphatic alcohols of the fatty acid series made jointly in the Laboratory for Organic Chemistry, directed by Professor E. Emmet Reid, Johns Hopkins University, and in this pharmacological laboratory, tests were made to determine whether any of these alcohols exerted a local anesthetic action. As a starting point for such experiments, 1% solutions of the 18 aliphatic alcohols were made in 95% ethanol. For the study of their local anesthetic effect on animals these were diluted 1 to 10, yielding a concentration of the alcohols of 1:1,000 in 9.5% ethanol. Alcohols containing more than 10 carbon atoms, which were not soluble to the extent of 1:1,000, were used in saturated solution. Pharmacological tests were first made on the conjunctival and corneal reactions of rabbits and then on living frogskin by well-known standard methods. While studying the anesthetic effect on frogskin, we made a note of (1) the rapidity of onset of anesthesia, (2) the duration of complete anesthesia, (3) the time of cessation of all anesthetic effect, and (4) the concentration of the alcohol used.