This paper reviews the present state of arts and the expected future developments on the side of electronic engineering, with its possible influence on medicine.
Emphasis is placed on the importance of modular systems, from the standardization, ease of construction and maintenance, and other industrial points of view. The tendency toward miniaturization and micro-module system is also discussed.
Mention is made of the possible mode of coperation between electronic engineering and medicine in the field of research toward the development in electronic and control engineering as well as in medicine.
The rapid expansion of information processing techniques will produce profound influences on medicine, both in diagnosis and in hospital management, which might better be called an introduction of system engineering to medicine.

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Progress of research and industrial development in the field of high polymer chemistry during these thirty years are very remarkable, and succeded to give various excellent results, such as the improvement in quality of natural and synthetic elastic high polymer, the discovery of many new synthetic rubber, the appearance of new processing technology or the development of new applications.
The authors review in this paper the recent progress in the medical field brought about by the studies of high polymer.
Uptill now, so many medical articles have been made of elastic high polymeric substances, and they have been useful for medical doctors and directly consumers. However, recent rapid progress in the medical treatment brought about to use these articles in the living body directly contact with it for long period. So that, in ordere to make by the way of trial many kinds of artificial internal organs, to study transplanting, to study clinically with new catheter for medical treatment of serious pulmonary tuberculosis or hydrocephalus, the high polymeric substance, which does not give any living body reaction, is necessary.
Silicone rubber and urethane rubber for medical purposes are now being studied as a new medical rubber materials, but the “specially cured natural rubber”, which the authors studied and developed, was found to have almost on living body reaction and to be excellent inprocessing properties and dynamic properties. At the same time the physical properties of this material showed similar physical properties of internal organs.
The authors prepared by the way of trial many kinds of artificial internal organs and new medical treatment apparatus with mainly this natural rubber for medical purposes, and the animal experiments, and the clinical studies of these articles at many medical institutes and hospitals have showed very good results.
At the progress in the medicine need new materials and the appearance of new material contributes the progress in the medical science, close contact of medicine and engineering was thought to be more and more necessary for the both developments.

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Any artificial control system, which bears the complex multi-loop connection as in the biological regulatory system, has not be costructed notwithstanding the progress of control engineering with rapid strides. On the other hand, the living things has inexact character in some points comparing with artificial machine, and may fall into discompen-sation in abnormal circumstances or in disease. The author has made an attempt to construct a new control system by the organic connection of biological system with artifi-cial system.
At first, the mechanism of blood pressure regulation as a living system is analyzed and the simulation of the system of blood circulation is indicated by analogue computer circuit. It is elucidated that the stabilization of blood pressure by means of an external blood reservoir of large compliance is not accomplished without the biological regulatory mechanism.
The effect on the blood pressure and other phenomena by the stepwise or periodic blood transfusion and hemorrhage was investigated to obtain fundamental data for the artificial control of circulation by means of blood transfusion and hemorrhage.
The regulatory system of blood pressure by the carotid sinus was examined by means of s-and-ω analysis. It is indicated that the system has a high stability with wide phase and wide gain margin. An apparatus named pressure amplifier by which the input pressure is transfermed into the output pressure with any given transfer function is constructed. Using the pressure amplifier, the systemic blood pressure of animals was trnsformed and given to the isolated carotid sinus. Thus, the loop characteristics of control system may be artificially changed at need. The improvement of stability of blood pressure was observed by the increase of the loop gain. However, when the transfer function of the pressure amplifier has some frequency characteristics, the undulative changes in blood pressure were brought about.
Similar improving effect was observed also by the increase of loop gain of the system of blood pressure regulaton by the aortic baroreceptor with a feedback electric stimulation of the depressor nerve.

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By applying both Echo Capsule, a new type of passive endoradiosondes and Radio Capsule, a battery contained type, to medical experiments, I have obtained following results.
(2) Temperature measuring endoradiosondes,
(i) There is some temperature difference at various portions of the esophagus.
The dorsal portion of the trachea has a little low temperature and the ventral portion of the right atrium has a little high compared with that of other portion of the esophagus
(ii) In the stomack, the temperature is about 0.5°C higher than in the mouth
(iii) When a patient takes a test drink (200cc 20°C water), the intragastric temperature falls immediately considerable degree from the base line and it restores slowly and exponentially to the base line within thirty or forty minutes. This exponential curve of intragastric temperature after taking test drink is called gastrothermogram and from this curve, following numerical value can be obtained.
(a) volume of gastric juice
It concerns with the degree of temperature fall from the base line. When gastric juice is scarce, the degree of temperature fall is great, and when abundant, the fall is small.
(b) ejection volume of intragastric contents from the stomack to the duodenum.
From two gastrothermograms obtained successively at intervals of thirty or forty minutes, the ejection volume in that interval can be calculated.
(c) Area of gastric wall contact with intragastric contents.
The temperature of intragastric contents rises by absorbing heat mainly from the gastric wall by means of conduction, therefore a equation representing relationship between intragastric temperature and time can be obtained. From this equation and a gastro thermogram, the area of gastric wall contact with intragastric contents can be calculated.
(iv) Thermal over-shoot phenomenon was seen in a few cases
(v) By detecting temperature rise of endoradiosonde due to the resolution heat of sodium perborate by catalase contained in the red bood cells, the source of intestinal bleeding may be localized
(2) pH measuring endoradiosondes they were applied in a few cases and good results were obtained_

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Several kinds of transducers are now used in practical phonocardiogaph. In view of energy transfer from the tissue to the transducer, mechanical impedance matching is important as in other engineering field. However, problems on mechanical impedance matching have been very little studied in phonocardiograph.
Two kinds of transducers, air transmission type and direct contact type were measured.
From the point of view of impedance matching, the mechanical impedance of an air transmission type was too low to get a good matching. In our experiment, signal to noise ratio of the air transmission type was worse than the direct contact type.
In this report studies mainly on the direct contact type transducer are presented.
To investigate the function of the transducer in actual use, mechanical impedance of the transducer and the tissue, arm and thorax, were measured.
Mechanical impedance of the arm was very similar to that of the thorax.
Therefore, further experiments were carried out by using the arm because of its convenience.
And also the results showed a resonance at which the impedance became resistive. The impedance became elastic below resonance and mass reactance above resonance. These mechanical impedance are equivalent to the series impedance of the electric circuit of C, R and L.
This equivalent circuit of the tissue is added to the equivalent electrical circuit of the transducer to get the equivalent model of the transducer in actual use. This equivalent model shows a double resonant system and represents the actual character of the transducer.
Under these considerations, several transducers with different impedances were examined by the arm to investigate efficiency of energy transfer and frequency response of transducers.
The results showed what was estimated by the equivalent model mentioned above.
Based upon these studies, the direct contact type transducer with mechanical impedance nearly to that of the tissue was constructed and presented a good results in its efficiency and ambient noise di

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