With regard to the estimates, for hearing threshold.variation of the threshold of the normal ear during long term, and the effect of training on threshold, automatic audiometry fixed in frequencies at 4000cps for 4 min., using continuous tone and interrupted tone(10 ips, partially 4 ips) was repeatedly performed 5 times in1or 2 weeks. The subjects employed consist of the following 2 groups;in the first group the subjects were well trained with this testing method, in another group the subjects had no its experience.
The conclusions obtained from the present study are as follows:
1.Hearing threshold
1) The variations of threshold in all but 3 of the untrained subjects were essentially similiar to those in the trained subjects and distributed within ±5db, but at times they were above 10db.
2) Three individuals of the untrained subjects indicated a marked threshold-rise or significant fluctuation in continuous tracings, particularly in the first and second test.It could be suggested that the irregularities of such results may be due to fluctuations in attention and changes in the subjects criteria of hearing or some mechanical factors.
3) TTS for 4min in the trained subjects seemed to be a lower amount and smaller variation than that in the untrained subjects.While the values of TTS by continuous tracings were larger than those by interrupted tracinge in the untrained subjects in the trained subjects there are little difl erences between continuous and interrupted(10 ips) tone, and interrupted tracings(flips) indicated u lower value of TTS.
2.Excursions of Bekesy tracings
1) The mean magnitude of excursion amplitude of Bekesy tracings, by using continuous tone and interrupted tone, in the untrained subjects were found to be more reduced and smaller on than that in the trained subjects.
2) The significantly reduced width in the process of the continuous tracings was shown in some of the trained subjects.

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