Recent advances in muscle physiology were briefly reviewed in respects of subcellular structure of skeletal muscle fibre, excitation-contraction coupling, effect of electrical field stimulation, contractile mechanism and dynamics of muscular contraction.
Discovery of the transverse tubular system (T-system) and the elucidation of the role of calcium ion bound by the sarcoplasmic reticulum in the initiation of contractile reactions suggested that the ion may connect the excitation in the surface membrane to the contraction, and that the stimulation of the coupling site directly by electrical current may produce the contraction.
The sliding-filament theory in sarcomere was proposed on the basis of the observation of myofilament by electron microscope and some intimate physiological evidences. Ih the dynamics of muscular contraction, however, the series elastic component and the characteristic system for energy mobilization complicate the relations among muscle length, tension and shortening velocity.

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The effect was studied of various physiological parameters of human lung on the optimum respiratory frequency and the minimum respiratory work by means of analog computer. We accomplished a human respiratory analog model in which the respiratory frequency and the tidal volume were controlled under the condition of minimum respiratory work when alveolar ventilation was given.
The end-tidal lung volume changed according to the respiratory frequency and to the tidal volume. It was influenced by physiological parameters of the lung, i. e., lung-thoracic compliance, viscous resistance, turbulent flow resistance, and dead space. The end-tidal lung volume was the sum of basal static functional residual capacity and excessive dynamic expiratory reserve volume which was represented in terms of respiratory frequency and intra-thoracic pressure. The respiratory total work was calculated from the pressure given to the thorax and breathing air flow. The work expended against the elastic resistance increased according to the increment of excessive expiratory reserve volume. The increase of dead space caused the decrease of respiratory frequency and the increase of minimum work. The increase of lung compliance resulted in the decrease of both the respiratory frequency and the minimum work. The increase of viscous resistance produced the decrease of respiratory frequency and the increase of minimum work. The turbulent flow resistance showed the same tendency as the viscous resistance. This human respiratory analog model gave reasonable response transitory time of optimum respiratory frequency and tidal volume against the step change of alveolar ventilation

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An attempt was made to produce a practical systemfor automatic diagnosis of ECG, whereby operatian for data acquisition and processing was made simple and effective.
The system consists of a three-channel electrocardiograph, a scanner, an analog-to-digital converter (sampling frequency per channel 333 cps), an MADIC-IIA electronic digital computer (storage capacity 4096 words in a magnetic drum) and an X-Y plotter.
The digitalized data of the second heart beat during 4. 2 seconds of recording with Frank's lead system were smoothed by a weighted moving average method. The magnitude changes in spatial ECG vectors was used for automatic pattern recognition of ECG waves. By the application of the above method, the points of beginning and end of the waves were satisfactorily estimated in 97 per cent of 100 patients. Automatic diagnosis was performed on the basis of logical operation employing amplitudes and time intervals of ECG, and 89 per cent of the results of computer diagnosis coincided with those diagnosed by a cardiologist on the conventional lead ECG.
The average time required for data acquisition was 15 minutes and that for pattern recognition and diagnosis was 5 minutes.
Methods for noise elimination and data processing of ECG were discussed.

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Consideration of AC steady state aspects of electrode polarization is very important in electrochemical studies of biological systems such as impedance plethysmography and development of electrode for pacemaker and metal microelectrode. Many investigators reported that the zero drift of electromagnetic blood flow meter is seriously influenced by the material of the electrode.
In this paper the AC characteristics of metal electrodes at very low applied voltage (<20 mV) are examined in order to study the electrode of blood flowmeter.
The polarization impedance of platinized platinum is dependent on the diffusion rate of reactive substances, and it is thus considered as the Warburg's impedance.
As for the electrodes of usual metals such as platinum, gold, silver, and copper, however, the polarization impedance is likely be influenced more by the activation polarization or the resistance polarization of electrode surface than the diffusion rate.
The electrode impedance is very unstable and have very poor reproducibility. The characteristics of metal electrodes are seriously influenced by the pretreatment technique, electrical and chemical history, and the measuring conditions of electrode.

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In the studies on the artificial heart, it is one of the most important problems to determine a waveform of pumping action reqired to keep the blood circulation in physiological state. To do this, the authors have developed a pressure generator which can generate arbitrary fluid pressure in various waveforms. The pressure generator, called the PRESSURE GENERATOR FOR UNIVERSAL USE, is characterized by adopting the closed system of the air-driven method as its driving mechanism and utilizing a digital computer as its control. system, the latter device providing us with a wide range variety in waveforms. The pressure genrator consists of the following components :
(1) Mechanical part :
Inside the closed piston cylinder sealed with a bellofram, the air pressure is generated in accordance with the piston movement. The shaft of the piston is driven by a pulse-motor which rotates by a fixed angle forwards or backwards faithfully corresponding to each pulse issued from the pulse generator. The excursion of the piston is altered through the Cardan gear mechanism without any interruption.
(2) Pulse generator :
The digital computer FACOM 331 is used as the pulse generator controlling the pulse-motor. Many patterns of waveforms are stored in the memory device (magnetic drum) of the computer. To select one of the patterns and to switch from one to another are monitored by a program stored in the core memory of the computer. Using this pressure generator, the development of the artificial heart will be facilitated.

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In the transmission system using ordinary telephone networks for sending and receiving medical informations such as ECG and EEG, from individual homes and clinics to the central hospital, the problems are random-noise, crosstalk, fluctuation in level, nonlinear distortion, phase distortion and impulse-noise. From the viewpoint of maximum improvement of signal-to-noise ratio, FM system is better than AM, PFM and PDM.
Non-linearity and fluctuation in level are mostly due to telephone transmitter characteristics. For avoiding these draw backs, we used the telephone transmitter in the vertical position and at the acoustic pressure of 10 μ bars.
The effect of phase distortion on the final signal-to-distortion ratio is calculated and the relation between that effect and the frequency deviation in the FM system is obtained.
Dual-channel reversed frequency deviation system was in order to remove the effect of impulse noise. This FM system designd for medical data transmitter by the telephone system possesses satisfactory operation.

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