The aims of the biological engineering related to the auditory system are to reveal a mechanism processing the auditory information and to presume the signal transmitting in the auditory system. This paper reviews the auditory model which consists of a basilar membrane and auditory nervous systems. Such a model based on the physiological researches is expected to suggest some good ideas on the processing of the speech signals. Some models for the automatic speech recognizing system are also described in this paper.

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A new induction pacemaker and a demand induction pacemaker, using high efficiency r. f. energy transport circuits, which have been designed after careful analysis, are described. The energy of a stimulus of the induction pacemaker is continuously transmitted in the interval of two stimulating pulses from outside the body and stored in the circuit inside the body, where it is discharged and transferred to the heart as a stimulating pulse. Therefore, the rhythm of the stimulating pulses is not disturbed from external electrical noises. The induction pacemaker is operated as long as 40 days with a battery of 7. 8-V, 420 mAh. The life expectancy of the receiver is more than 10 years.
The demand induction pacemaker consists of a transmitter and a receiver of a demand circuit for which energy is supplied from the transmitter.
The clinical experience in two cases, a 16-month-old infant and a 29-year-old adult, is also described. The methods of attaching a transmitting coil to the patient are evaluated.

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[Purpose] Experimental and clinical studies on the factors related to breast thermography have been carried out for the purpose of determining the diagnostic accuracy of breast diseases.
[Method] 1. Experimental studies Hot spots, in constant temperature and in various diameters, were used as phantoms of malignant tumors. After the paraffine layers in various thicknesses (7, 10, 15, 20 mm) covered the spots, thermograms were taken with “Barns Ml infrared, camera” at constant intervals during experiments.
2. Clinical studies : Thermograms of breast diseases, proved histologically, were. statistically investigated and analyzed.
[Results] 1. Experimental studies : Limitations of the thickness of the paraffine plate were suggested in a series of diameter of the hot spot, which enabled us to take thermograms. It was found that there was a linear relationship between the thickness and the diameter.
2. Clinical studies : Diagnostic accuracy rate for breast cancer is low when the diameter of the tumor is smaller than 20 mm. Diagnostic accuracy rate is higher in the localized type than in the infiltrating type.
In our experience it was found that the combined use of clinical, mammographic, echographic, and thermographic examinations gave the best diagnostic accuracy rate for breast cancer.
Thermography is not enough to be solely relied upon for mass screening for breast cancer but it represents an addition to other methods of diagnosing breast lesions and deserves further investigation.

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An infrared optometer, which is capable of continuously measuring the refractive power changes in the human eye, and a target display system with variable artificial pupil have been devised. Using these devices, eye accommodation has been observed and the differences of the accommodative responses among various effective pupil diameters have been investigated.
On steady state accommodation, it has been observed that the refractive power decreased as the pupil size decreased. Amounts of the decreases were measured for three subjects and it was made clear that they were unrelated to the magnitudes of accommodative stimuli and the luminance of the target. It was found that the amounts depended only on the pupil size and were represented by a reverse function of the pupil diameter. Further, it was found that they were closely related to the half values of the depth of focus of the eye obtained by K. N. Ogle. Therefore, a hypothesis has been deduced that at steady state, visual point is placed on the position farther than the object with an offset, which is equal to a half of the depth of focus, so as to produce the minimum detectable amount of blur on the retina. The size of the minimum detectable blur has been estimated as 24 At on the retina from the observed accommodation offsets.
In order to verify the hypothesis, transient responses of accommodation to stepwise target motion were investigated. When the target moved from near to far, very slow responses (response time ranging within 2-5 sec) were often observed for small target motion. Quantitative investigation revealed that this kind of response was caused by the depth of focus, and the eye can accommodate stably on only the farther point among the two points where the critical amount of blur was produced on the retina.
Finally, in human eye accommodation, a control algorithm for steady state accommodation is considered to be used so that the eye increases its refractive power when the blur on the retina exceeds the threshold value and decreases when the blur is below the threshold.

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本講座は生理学を専門とされていない方々, 特にエンジニアサイドの方をも対象としたものとのことゆえ, 1) 生理学専門の術語の使用をなるべく避けて平易な説明を心がけること, 2) できるだけ邦文々献を引用することに極力留意し, 網膜で視覚の情報がどのように処理されているかをおもに著者らの立場を中心に述べたい。生理学という学問の性格上, 以下に述べる実験から得られた結果はすべてヒト以外の動物を対象としたものであることは, あらかじめ御了承いただきたい。

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