Necessity for consideration of present hearing tests.-Testing of tonal limits considered; present tests accepted as satisfactory. Anomalous results of comparison of perception of the monochord by air and bone conduction.-The Rinne, Schwabach, Weber and Bing tests destructively criticized.-The Gellé and galvanic cochlear tests; Fraser's modification of Gellé's test.-Suggestions for the improvement of testing.-The "absolute bone conduction" test affords an absolute index of the perceptive component of hearing (nerve function).-Mechanism of transmission of sound waves through the skull (bone "conduction").-Quantitative determination of hearing power; results expressed on a distance basis are to be preferred; use of tuning forks in obtaining such results.-The mathematics underlying this use of tuning forks.-Accurate quantitative estimation of nerve function (the perceptive component of hearing).