The number of analyses has consistently doubled every 5-6 years in the department of central clinical laboratory of the University of Tokyo Hospital and almost all teaching hospitals have found the same within a recent decade. The simplified and/or automated procedures of analysis were inevitably developed in the laboratory medicine.
Paper tests have made urinalysis extremely simple. For example, phenylketonuria, one of inborn errors of metabolism, associated with a marked degree of mental retardation, is now easily detected by paper test. The radioimmunoassay have permitted the clinicians to obtain easily information. concerning the level of many peptide, steroidal andother hormones which are normally present in extremely small concentrations in the blood.
Recently automated analyzers such as SMA 12/60 and Coulter S have come into clinical use Their chief value is that large numbers of specimens can be processed rapidly with a minimum, personnel. On the other hand, entire series of testreliably performed has created a new aspect in. the field of clinical diagnosis of diseases. Investigation of large number of patients so testedsuggest that about 20 % of unsuspected but significant abnormalities are uncovered using multichannel automated analyzer. The use of automated tests as ascreening procedure in routine tests is almost surely beneficial.
In recent years, the biochemical requirements for emergency service are increasing and have become relatively complex. Unfortunately, all hospitals can not have adequate staff on call for 24 hours. The use of usual automated equipments, with the requirement for more specialized. staff, accentuates the problems. Under such situations, a development of a new automated analyzer for emergency service is urgently requested. This type of analyzer should be easy to operate, such as by push button, capable of rapid performance of tests which meet the minimum requirements, , should use no serum but whole blood and also be inexpensive.

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1. Implications of Biofeedback
Biofeedback is a procedure that if organisms are provided with (1) some new information it the form of perceivable stimuli, i. e., visual or auditory ones (single or pattern), which are transformed in intero-proprioceptive stimuli from internal responses such as heart rate, blood, pressure, or electrical activity of the muscles and the brain, and (2) incentives or rewards for changingor controlling the feedback, these organisms can learn to control voluntarily the physiological responses associated with feedback.
In the biofeedback process, there are two important principles to be considered. (1) The laws and procedures of instrumental learning (or operant conditioning) in which rewards (or reinforcements) are given contingently upon the changes of response. (2) The technique of shaping (successive approximation) -in other words, of immediately rewarding first very small, and hence frequently occurring, changes in the correct direction and, as soon as, these have been_learned, requiring progressively larger changes as the criterion for reward.
2. Biofeedback in Animals
It has been found that many autonomic responses can be instrumentally (or operantly) taught either to increase or decrease under the condition of ruling out the respiratory or overt skeletal responses. It is possible to learn a specific visceral response independently of some other ones. (specificity).
3. Biofeedback in Humans
Autonomic responses, EEG, and EMG are also modified in humans by the technique of biofeedback. From the point of the degree of changes, one is easy and the other, difficult. Therefore, the tasks for the future will be to improve the understanding of the laws and mechanisms involved in visceral learning and to improve the techniques for training the subject to produce larger changes more quickly.
The following factors should be investigated in the field of psychology and medical electronics : (1) mediation (cognitive process or respiratory and overt skeletal response), (2) timing of feedback, . (3) feedback mode (analog, digital, visual, auditory), (4) strategy for controlling response, (5) individual differences.
In therapeutic application, it is important that training be done, by the help of some feedback : equipment in the earlier stage of the therapy, and as training proceeds, patients become capable, of controlling their internal response, by themselves without the aid of feedback instruments in daily life situations.

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Some geometrical optical illusions are analyzed in terms of the perceptual field. Psychological distance is introduced which is different from physical distance, and this difference explains theillusion.
A theory is proposed which represents the psychological distance as a function of the field potential induced by the stimulus figure. By defining the psychological distance and line, the straight line and the length in the figure can be determined, and geometrical optical illusions cam be explained as distortions of the metric of the perceptual field.

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From the point of the optimal theory, the relationship between the branching structure and the mechanical characteristics of a tree was analysed in reference with such parameters as circum-ference, weight, bending moment, branch length and-branching angle, The study was based on a hypothesis that the optimal structure of a tree agrees the minimum energy loss.The total energy loss is the sum of the energy required for the construction which is proportional to the wood' volume of the branches and the energy consumption for supporting the weight of the branches and leaves which is equal to the elastic. strain energy. Results derived theoretically from the hypothesis are as follows : 1) The Maximum bending stress at each branching point is constant.2) The relation between the circurmference (C) at some point and the bending moment (T) acting on the branch is, T∝C³. 3) The relation between the weight (W) of all the parts of the tree peripheral to some branching point and C is, W∝C^2.5. 4) The relation between T and W is, W∝T^5/6. 5) The relatlon between the branch length (l) and C is, l² ∝C. 6) When C₀, C₁, C₂ are the circumferences of the mother and daughter branches and θ₁, θ₂ are their branching angles, the following optimal conditions for a dichotomy are derived;
C₀^2.5= C₁^2.5+C₂^2.5 and C₁³/ sinθ₂=C₂³/ sinθ₁.
These relations were examined, by measuring the varying size of branches, 76-286 in all, on seven different kinds of trees, and the very good agreements between the theoreiical and actual relations were confirmed.

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A model of mammalian muscle spindle consisting of transformer (viscous elasticity of intrafusal fibers), mechano-electric transducer and encoder has been developed based on the anatomical and physiological findings. All the parameters of the spindle are determined quantitatively, simulating the experimental data obtained from cat soleus muscle by P. B. C. Matthews and his coworkers.
The responses of the model show close agreement with the physiological data, explaining the effects of fusimotor stimulation on spindle sensitivities. As a result, following significant properties are explained. (1) Position sensitivity of the primary endings is increased in direct proportion to the stimulus rates of the static and dynamic fusimotor fibers, i. e., Γ_s and Γ_d, respectively. (2) Position sensitivity of the secondary endings increaseswith an increase in Γ_s. (3) Velocity sensitivity of the primary endings increases in direct proportion to Γ_d. (4) Velocity sensitivities of both endings decrease as stretching velocity of the muscle is increased. Furthermore, it is suggested that these sensitivity changes can be accounted forby way of variations of the viscous and elastic characteristics of the intrafusal fibers.

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An implantable socket is described for percutaneous electrical pathways in long-term intermittent monitoring, stimulation and energy transmission.
The shell of the socket is made of an acryl pipe. In the shell, a conductive rubber of 2.5 mm is housed, which serves as an electrical mediator between a lead wire in the body and a needle inserted via the skin. To insulate the conductive rubber from body tissues, the socket is filled with silicone oil of high viscosity and covered with a-silicone rubber sheet. The final dimension of the socket is 15 mm∅ x 7 mm. The needle is made of a 27 G disposable hypodermic needle and insulated by silicone varnish except 2-3mm at the tip, which makes contact with the conductive rubber in the socket.
The durability of the socket was tested in experiments in which the needle was stuck into the socket 4, 000 times consecutively, and contact resistance and leakage resistance were measured every 50 times. Contact resistance remained below 10 Ω, and leakage resistance above 100 MΩ. The socket was implanted in a dog's chest wall for 67-120 days. No tissue abnormalities were observed at gross examinations.
Possible applications of the socket to clinical and research purposes are discussed together with the consideration of some limitations in the use of the socket.

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A system (Fig.1) has been constructed, which is able to feedback to the subject information about the difference between short-term average amplitude or frequency of his alpha waves and a certain preset reference level. The property of feedback control of human alpha activity was examined by this means. First, occipital EEG of the subject was filtered by 8-13 Hz band pass filter and the amplitude or the number of zero-crossing points for a past short interval (routinely 4 sec) were calculated by a special counter circuit. The output of the counter was compared with a reference level and the difference was converted into an auditory signal (characteristics of the converter is indicated in Fig.2) and indicated for each 0.5 sec to the subject.
Using the above system a feedback learning experiment was performed on normal adults in their three states-eyes closed, eyes half-opened and eyes opened. The results (Fig.4 and 6) were as follows : (1) Subjects were capable of controlling the alpha amplitude in the range between their resting, closed eyes-level to opened eyes-level. In controlling the alpha frequency the range was 9. 5 to 11. 5 Hz. (2) State with the eyes half-open showed widest range of control of both amplitude and frequency.
Discussions were made on the possible improvement of feedback signalling and on the strategies used by the subjects.

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