The methods developed in Part 1 are applied to the analysis of hearing sensations, in particular to experiments by Shower and Biddulph, and by Bürck, Kotowski and Lichte on the discrimination of frequency and time by the human ear. It is shown that experiments of widely different character lead to well-defined threshold "areas of discrimination" in the information diagram. At the best, in the interval 60 - 1.000 c/s the human ear can discriminate very nearly every second datum of information; i.e. the ear is almost as perfect as any instrument can be which is not responsive to phase. Over the whole auditory range the efficiency is much less than 50%, as the discrimination falls off sharply at higher frequencies.The threshold area of discrimination appears to be independent of the duration of the signals between about 20 and 250 millisec. This remarkably wide interval cannot be explained by any mechanism in the inner ear, but may be explained by a new hypothetical effect in nerve conduction, i.e. the mutual influence of adjacent nerve fibres.