The author devised a new method of play audiometry. This is an improvement on the peep show test originated by Dix and Hallpike, which uses, in place of pictures, an electric locomo-tive set more attractive to children as a reward. When the tested child presses a button at hand hearing a tone, an electric locomotive drawing passenger-cars starts, signal lights go on and off and crossing bars go up and down. A panorama is developed in which stations and tunnels are placed. At the test the author used conditioned reflex and used light stimulus as nonconditioned stimulus. In order to carry out the test by only one person, the author so designed that opening and closing of the whole circuit could be operated by a switch on the tester's side. It was also arranged that the switch could be operated in the test room when conditioning, and could be operated in the neighboring instrument room when testing. A magic mirror was put in the wall between test room and instrument room and the test was performed by observing actions of the child. With the child who disliked wearing of the receiver, biaural hearing was tested on the free field.
The author studied some problems on the measurement, test results and application ages in the 230cases tested by this method during the past year. She also measured hearing acuity of normal children aged 3-6. She also investigated the test reliability by means of a study on threshold variations between test and retest, and a comparison with the thresholds measured by the standard pure tone audiometry (hand rising method).
The results obtained are as follows.
(1) The measurement of hearing thresholds by this method was very difficult with children under 3. The application limit of play audiometry is considered to be about 3 years of age.
(2) In general, the test was easy with normal children, with mildly and severely deaf child- ren and was difficult with moderately deaf children.
(3) The hearing thresholds of normal children aged 3 - 6 showed an average rise of 5-20db as compared with those of normal adults. The thresholds were high especially in low tone and high tone areas and tended to approach those of adults with the increase of ages. The audiogram was knoll-shaped.
(4) When the test cannot be performed more than once, it must be always borne in mind that the hearing might be better than the thresholds obtained show.
(5) With normal children and older children, thresholds near true ones can often be obtained at the first test, but with deaf children especially moderately deaf children it is dangerous to de-termine thresholds at the first test. True thresholds, however, can be obtained at the second test.
(6) With younger children aged 3-5, determination of thresholds in low tone and high tone areas requires circumspection.
(7) This method was particularly valuable for determination of hearing acuity in profoundly deaf children and for detection of residual hearing in totally deaf children.
(8) In pre-school age children the results obtained by this method are superior to those obtain- ed by the standard pure tone audiometry (hand rising method).

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The author divided young guinea-pigs into 7 groups control group, V. B_1-, V. B_6-, V. B₁ B_6-, orotic acid-injection groups, group under 8% oxygen, group under 10% carbonic acid gas. The author stained the P-tase (alk. P-tase or acid P-tase) in the cochlea of the inner ear according to the modified Gomri's method exposing the animals to white noise of 100-105 phons for 5 hours every day during one to five weeks. Parallel to this he performed quantitative analyses of serum P-tase according to Fukuyama-Yamashita's method and of serum free aminoacids according to Yemm & Cocking's method, and examined carbohydrate metabolism of sensory tissues and made a conjecture upon acoustic mechanism from energy metabolism of an organism. The results obtained are as follows.
(1) P-tase is physiologically distributed in the cochlea of the guinea-pig, and is particularly found in the sensory tissues of hair cells, spiral ganglion cells etc. and in stria vascularis. Alk. P-tase in spiral ganglion cells is in some degree more deeply stained in the cytoplasm than in the nuclei, but acid P-tase is better stained in the nuclei. And in the hair cells both alk. and acid P-tase are more deeply stained in the nuclei than in the cytoplasm.
(2) P-tase in the cochlea is generally hard to stain perhaps owing to decalcification, and the dyeing of acid P-tase is unstable.
(3) Under the intense noise exposure alk. P-tase in the cochlea shows remarkable change previously to morphological change in the cells.
(4) The remarkable decrease of alk. P-tase in the cochlea can in some degree be prevented by the use of carbohydrate metabolism co-ferment (V. B₁) and protein metabolism co-ferment (V. B₆). V. B₁ was comparatively effective in single use, and the combined use of V. B₁ B₆ was also effective. Acid P-tase had generally the same tendency as alk. P-tase, but the details were unknown owing to its unstable staining property.
(5) The change of alk. P-tase is remarkable under low percentage of oxygen and high percentage of carbonic acid gas, and it is experimentally considered to be primarily necessary.
(6) The change of P-tase in the cochlea has the same tendency as that of serum P-tase. The serum alk. P-tase value of animals of noise exposure 2weeks, showed 16.2^mM/l (0.94) and that of the group of 4weeks exposure 6.6^mM/l (1.06), in contrast with the higher value of alk. P-tase of the n. rmal young guinea-pigs at 37.7^mM/l (acid P-tase: 2.52^mM/l). The remarkable decrease of alk. P-tase in the serum can in some degree be also prevented by the use of the co-fements (V. B₁, V. B₆). Accordingly it was found that intense noise influences metabolism of the whole body as well as the affected area.
(7) From the standpoint of the biochemical energy theory attributing energy sources of the nerve tissues to carbohydrate, the supply of P-tase (ATP, DPN etc) and V. B₁, the so-called ferments of glycogenesis, is considered to be primarily necessary to the activity of the sensory tissues as well as oxygen.
(8) Once the tissues suffer irreversible change by lack of oxygen and disturbance of fermentative metabolism, the restoration of the function is considered to be hopeless.
(9) Unless animals are under extreme loss of oxygen, Embden-Meyerhof Cycle is considered to be more intimately concerned with loss of metabolism than is generally supposed.

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The author observed the cochlear blood circulation in the slightly anesthetized guinea pigs by means of the impedance plethysmography. This method is based upon the principle that changes in the blood volume in a given part cause changes in electrical impedance in the same portion(Fig. 1).
Two electrodes were inserted carefully into the basal turn of the cochlea 2 to 3mm. apart with a microboring machine and fixed by dental cement(Fig. 2).
Thus the changs of the cochlear circulation of the living guinea pigs in the physiological and pharmacological respects were observed.
All drugs were given intravenously through a polyethylen tube inserted into a jugular vein.
The results obtained are as follows
1. By the occlusion of an artery, the amplitude of the puls wave at the peripheral small artery decreased parallel to the degree of the occlusion(Fig. 3).
The increase of the amplitude means an increase in the blood flow and conversely a decrease of it means a decreas in blood flow at the given part.
2. The cochlear blood flow was very stable and constant under normal physiological circumstances.
3. Anoxia caused a marked increase of the amplitude, but it abruptly decreased in 30 sec. to 2 min. and became almost unnoticeable. By the resumption of respiration, the amplitude completely recovered and schowed a remarkable increase without an artificial respiration.(Fig. 4 a, b).
The breathnig of a high concentrate 02 caused a decrease of the amplitude, namely the cochlear blood flow(Fig. 4c).
The breathing of a mixture of 10% CO2 in oxygen caused a marked increase of the amplitude under an artificial respiration(Fig. 4d).
4. Alkalosis, produced by the infusion of 10cc/kg of 7 % sodium bicarbonate solution, markedly increased the amplitude of the pulse wave and respiratory wave, continuing about 10min.
Acidosis, produced by the infusion of 4cc/kg of 0.8% ammonium chloride solution, tem-porarily decreased the amplitude. But the very increase was sometimes observable contrary to the expectation(Fig. 5 a, b).
5. Adrenaline, in dose of 0.01mg/kg, caused a decrease during the first few seconds, and then a remarkable increase of the amplitude, but in 2 to 3 min. later, the amplitude again decreased. Noradrenaline, in a dose of 0.2mg/kg, also caused a decrease at first and then an increase, but no subsequent decrease.
The difference seems to come from the difference in dosage(Fig. 6a, b).
6. Acetylcholine, in a dose of 0.001mg/kg, temporarily increased the amplitude(Fig. 7).
7. Pilocarpine, in a dose of 0.1mg/kg, caused a demonstrable increase of the amplitude and simultaneously a decrease of the pulse frequency. But the recovery in frequency could be transiently observed, therefore the author concluded that pilocarpin dilated the cochlear blood vessels and initially decreased, subsequently increased the cochlear blood flow(Fig. 8).
8. Atropine, in a dose of 0.2mg/kg, caused a slight decrease of the amplitude, namely the cochlear blood flow(Fig. 9).
9. Imidaline(Priscol), in a dose of 1mg/kg, caused at first a decrease, and in about 1 min. a considerable increase of the amplitude, which continued about 6min(Fig. 10).
10. Papaverine, in a dose of 1mg/kg, caused a dramatic increase of the amplitude continuing about 6 min.
Papaverine was the most effective drug to the cochlear blood vessel in these experiments.(Fig. 11).
11. It is noteworthy that nicotinic acid, in a dose of 10mg/kg, did not cause any change in the amplitude but decreased clearly the pulse frequency. Therefore, the author concluded that nicotinic acid did not increase the cochlear blood flow (Fig. 12).
12. Kallikrein, in a dose of 0.1u/kg, also dis not cause any change in the amplitude(Fig. 13).
13. Amylnitrate, inhaled about 20 sec, caused a marked increase in the amplitude(Fig. 14).

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