Abstract
The scope of this experiment is to find powerful anesthetics to be used on tympanum. The mucous membrane of the external auditory canal of the guinea-pig is very adapted for the estimation of susceptibility to pain. After the application of local anesthetics dissolved in propylene glycol (PG) on the mucous membrane, a uniform mechanical stimulus was applied thereon and the mode of responses was investigated, recording the time-interval between the initiation and disappearance of responses and comparing such a record of one drug with that of another. The effectiveness of drugs was expressed as reciprocal of time. Results : (1) PG has no surface anesthetic effect. (2) Above certain concentrations nupercain-HCl, cocain-HCl, anesthesin, phenol, and menthol, each dissolved in PG, exert local anesthetic actions and the intensity of such actions is in the order named. (3) Among the solvents such as PG, glycerol, olive-oil, and water, PG is the most effective for potentiation of the anesthetic effect, while the phenol alone acts more effectively when dissolved in water than in PG.
