THE LOUDNESS growth in the normal ear adheres to a rather precise formula in conformity with the corresponding increase in intensity. At 1,000 cps a one to one ratio is obtainable between the sensation units of loudness and the decibels of intensity, while for all other cycles, the growth of loudness follows the equal loudness contour of Fletcher and Munson. 1 The growth of loudness is diminished by an obstructive lesion in the external or middle ear. It is said that loud sounds are reduced to the extent of the impairment in decibels at threshold. Undoubtedly, this reduction was observed in some cases. However, it is open to question whether a barrier in the path of a powerful stimulus has the same effect as the reduction in the intensity of the stimulus at its source. If the obstruction causes a rise in threshold of 20 db., it means that the