Clinical and laboratory tests consist of those for patient examinations and those for sample examinations. Medical-electronic apparatus are indispensable as instrumental analytical techniques to the sample examinations in chemical laboratories as well as to the patient examinations. Many books and papers have been published on the electrotechniques applied to analytical chemistry, but few of them on those applied to the clinical chemical analysis. The author briefly treats those apparatus used at present in the clinical chemical laboratory, as well as instruments which will be used practically in the near future.
It is emphasized that, from the special character of clinical chemical tests, medical-electronic apparatus should be so designed as to make completly automatic analysis, and that the education of techniciens who operate the apparatus should be improved by introducing fundamental electronics in it.

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The pattern diagnosis of electrocardiograms (EKG) by means of linear discriminant functions was undertaken with a digital computer. With X, Y and Z leads of Frank's scalar EKG, 27 parameters composed of amplitudes at 8 points of QRS apart at an interval of 10 msec and the maximal T amplitudes were manually measured. Forty-five EKG's consisting of three groups, Normal, left and right ventricular hypertrophy (LVH & RVH), -were used as material to derive a set of linear discriminant functions.
In order to differentiate two groups from each other by means of a linear discriminant function : F=L₁X₁+L₂X₂+………+L_nX_n+C F : discriminant value X₁, X₂, …………X_n : amplitudes of QRS and T L₁, L₂, ……… L_n : discriminant coefficients C : constant
A summation of the products of the measurements of the amplitudes, from X₁ to X_n, and the discriminant coefficients, from L₁ to L_n, respectively is made, then a constant C is added. The decision as to which group an EKG pattern belongs to is made according to whether the sum, that is, the discriminant value F is positive or negative. The discriminant coefficients, from L¹ to L_n, and the constant C were derived by the computer in such a way that the formula will give the best discrimination.
The derived formulae were fed with 79 EKG's which did not include the material-EKG's and consisted of the 3 groups of Normal, LVH and RVH, so that one could see whether formulae were able to make differential diagnosis of these 3 types of EKG patterns when applied to clinical series of EKG, S.
A set of 27 dimensional linear discriminant functions derived from all the 27 parameters discriminated well any of two combinations out of the three groups from each other when applied to the series of material-EKG's, but not so satisfactorily when applied to the series of other 79 EKG's. This may have been due to the insufficiency of the number (about 15 for each group) of the material-EKG's in comparison with the size of the dimension (27 of the formulae.
In order to overcome this crucial difficulty, a set of 8 dimensional linear discriminant functions was derived from the 8 parameters of each QRS of the 3 leads of X, Y and Z. Then, the three discriminant values calculated by this set of formulae with three QRS's of the three leads of the material-EKG's and the three maximal T amplitudes were used as parameters to derive another set of 6 dimensional linear discriminant functions.
When the series of 79 EKG's were put into this set of formulae, there were given correct diagnoses to 16 out of 22 Normal EKG's, 17 out of 25 LVH ones and 26 out of 32 RVH ones, 59 out of 79 in total (75%).
Based on these figures, it can be stated that the scheme of linear discrimiant functions works almost as good as average physicians in EKG diagnosis though not beating experienced specialists. Because of the simplicity of the computation, this scheme spends less computer time than other complicated but not much more capable programs for EKG diagnosis.

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A new intracardiac catheter micromanometer has been developed by applying the foil-type strain gauge, which is usually used to convert pressures into electric currents, as the cantilever of its transducer.
Experimental results show that the device is sensitive enough for clinical use as well as durable and economical with better frequency response without any lag of electric phase and better temperature responsethan in the case of the in vitro measurement method.

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The authors have attempted to apply gaschromatography, which has been used as a tool for chemical analysis, to respiratory gas analysis as a transducer. This modified gaschromatography is three-columns-two-detectors system and is accurate enough to obtain satisfactory measurements as well as capable of very rapid analysis of materials that has been impossible by the conventional gaschromatography. Experimental results reveal that the analysis can be made within two and a half minutes for dry gas and within three minutes to eight minutes for mixed gas that contains water vapour. Repeated use of thirty to fourty times after aging gave values in an acceptable range and no lowering of the column efficiency was noted. Further investigations are in progress to develop the methods of correcting data for volatile anesthetics and of treating contained water.

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An apparatus which automatically calculates and records the velocity of the vector loops of the vectorcardiogram has been made. Employing analog circuits, the following equation which was called the spatial velocity electrocardiogram by Hellerstein is automatically calculated.sV=√ (dx/dt) ₂+ (dy/dt) ₂+ (dz/dt) ₂
From the viewpoint of the electrocardiography this can be regarded as a kind of the first derivative electrocardiogram. Operational amplifiers, model K2-XA (Philbrick) have been used for the assemblage of the analog computer. Considering the frequency spectrum of the normal electrocardiograms, two kinds of time constants are alternatively employed for the differentiators : 1 msec for QRS complex and 10 msec for other lower frequency elements of the electrocardiograms. When sinusoidal waves were introduced, the response of this differentiator was 3 dB down at 159 c/s with the phaseshift of 45° with the time constant of 1 msec and was 3 dB down at 15. 9 c/s with the phaseshift of 45° with the time connt of 10 msec. The output voltage of the squarer, the adder and the square root circuit showed consistency with the calculated one up to 1. 5 volts at the input. The spatial electrocardiograms obtained by this apparatus showed good consistency with those obtained by manual calculation. The spatial velocity electrocardiogram can provide the time factor which is the weak point of the vectorcardiogram, for this pattern shows the velocity of the vector loop and the time course of the vector was recorded on the abscissa. The features of the normal spatial velocity electrocardiograms are found to be uniform and can be differentiated easily from those of abnormal ones, which is helpful for diagnosis.

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