This paper reviews the effects of electromagnetic fields, from DC to microwaves, on biological systems. Electrical properties of biological substances are briefly described. At DC, strong magnetic fields and steady DC electric fields are reported to produce several effects. At low frequencies, interest of many researchers is centered around stimulation, involuntary movements and shock hazards. produced by currents flowing through the body. Results of several experimental studies are cited. With shifts to higher frequencies, there seem to arise several points which need further clarification. At ultra-high and microwave frequencies, situations are quite different. Most of the effects produced are usually considered attributable to heat developed by electromagnetic energy dissipation, although several papers point out non-thermal effects. Calculations by electromagnetic theory and some experimental results are described. It is emphasized that several points need urgent solution.

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Recently there has been a remarkable progress of automation and data processing in clinical laboratory. However, the field of clinical bacteriology seems to have been left untouched by this trend of progress. In this study an automatic bacterial diagnosis (identification) was attempted. First, the routine examinations (18 tests) for bacterial identification were performed with each strain of micro-organisms detected. All of these data were coded as follows; 1 (positive), 2 (negative), 0 (unknown). The computer was made to memorize the biochemical characters of all gram-negative bacilli ('Master') beforehand. In the Master all were shown in a couple of figures (left and right figure). The left figure, which is expressed in the same way as data, represents the biochemical character. The right figure represents the gravity ('weight') of the corresponding biochemical character and it is graded into 4 classes, according to the previous reports ('G-3' ; the character that all (100%) varieties show, 'G-2' ; 99-90%, 'G-1' ; 89-70%, 'G-0' ; 70%>). Input data was compared with all micro-organisms of the Master. In the first step, the micro-organisms, whose characters weighted with 'G-3' fit completely to those of data, were selected. In the second step, the possibility (matching ratio to the characters weighted with 'G-3' and 'G-2') was calculated and printed out in each of the selected micro-organisms. Also the highest one was re-selected as a diagnosis and the name of this micro-organism was recorded. The discrepancy between the manual method and our computer method was 2%.

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By using a group of patients, consisting of 54 cases of systemic lupus erythematosus (SLE) and 24 cases of progressive systemic sclerosis (PSS), the usefulness of 7 kinds of hierarchical cluster analysis for the classification of collagen disease was studied. Distance between two cases represented by multi-dimensional vector was measured with the binary Euclidean distance. By comparing the results of these cluster analyses, namely, Nearest Neighbour, Farthest Neighbour, Group Average, Centroid, Median, Ward's and Flexible Form method with those of other multivariate analyses and the clinical classification, the following conclusion was drawn : 1. Forty five of 54 cases of SLE and all of 24 cases of PSS were correctly diagnosed by the Ward's method, which gave the best coincidence with the clinical classification in 7 clustering techniques, while other 6 techniques could not give good classification. 2. Two types of cluster growth was shown. One, observed in the Nearest Neighbour, Centroid and Median methods, was the type that a single major group grew from the beginning of the clustering process and increased in size by the addition of single patient and of small groups of patients who should rather have formed separate groups and fused at lower level. Formation of several clusters of equal size in parallel was another type which was observed in the Farthest Neighbour, Ward's and Flexible Form methods. These tendencies of cluster formation were also expected from their mathematical background. The former characteristics can be used for exception elimination and the latter, for subclass setting. 3. From these results, Ward's method would be considered to be the most useful technique among 7 clustering methods to apply to the analysis of the collagen disease such as SLE and PSS. This is compatible with the conclusion from the mathematical analysis of these clustering methods.
Relation of the cluster analysis to the factor analysis and linear discriminant function is also discussed.

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The development of an auto-blood grouping system of is our great concern. in this system, detection of the state of blood whether the blood in cells is agglutinative or not is considered the most important. Recently we have developed the new detection system which has the following characteristics :
(1) A semi-closed flat-shaped cell was devised for blood reaction, which is convenient for viewing optical-states of the blood.
(2) In order to convert an optical image in the cell into the electric signal, a vibrating fibre camera having a function of one-dimensional scanning was developed. Wave shapes of the signal corresponding to the optical image in the cell were obtained by this method distinctly and in detail (in high resolution), and in S/N ratio higher than 20 db.
(3) In the electronic signal processing unit, three following points were examined : (a) signal. level, (b) changing rate of the signal level with time and (c) total existing time width of the signal within the limited scanning time.
And we experimentally succeeded in detecting whether the blood is agglutinative or not exactly without being disturbed by external impulsive noises.

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Synchronization phenomena of the respiratory rhythm with the external stimulation are analyzed in order to develop the portable respirator by electrical stimulation of the phrenic nerve.
Applying a single group stimulation delayed in relation to the preceding inspiration, its effects on the interval between the stimulation and the following spontaneous inspiration are observed. The results obtained are called “the stimulation phase-inspiratory initiation time relationship”, and show two typical features : the stimulation causes inspiration to be delayed when the stimulation phase doesn't exceed the so-called switching point time, and the stimulation evokes inspiration when it does.
It is confirmed by experiments that this relationship is maintained even in the case of repetitive group stimulation, and the synchronizable stimulation period can be derived from the analysis of this relationship. The theoretical derivations are fairly consistent with the experimental results.

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A check-valve model has, been described for the purpose of understanding the characteristics of the expiratory flow. The diameter changes of the bronchi and the pressure distribution in the flow direction are calculated by a digital simulation technique. It is assumed that the airway is composed of the bifurcate branches which are the collapsible tubes with finite length because the ratio of the diameter to the length of the bronchi is not so small, the rigidity of bifurcations should not be ignored, and the displacement of the diameter caused by airflow is not so large. Mathematical expressions are derived and some calculated results are obtained in the case of circular cross section. In these numerical computations, the values given by Weibel's model is used as the geometry of the bronchial tree, and the effects of the expansion losses and the lung parenchyma are taken into account in a simple manner. It is found that the saturation of flow in IVPF (iso-volume-pressure-flow) curve is significantly affected by the compression of the branches between 2nd and 4th, and that maximum flow has dependence on the properties of bronchial wall, flow density and the degree of lung inflation related with the lung parenchyma. These results approximately coincide with the experimental results qualitatively and quantitatively in the overall IVPF characteristics under reasonable values of some parameters.

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The relationship between chest cage movements and changes in the transthoracic electrical impedance was studied with respect to three parts of the thorax, comparing the findings with simultaneously recorded respired air volume changes measured with a spirometer. The inductance pneumometer detected the dorso-ventral thoracic movements by measuring the mutual inductance. between two coils, distance of which varies with diameter changes of the chest cage associated with respiration. Transthoracic impedance was measured with a two-terminal, constant-current impedance pneumograph.
Coils and electrodes were placed on the upper, middle and lower part of the right thorax along the mid-clavicular line for the anterior chest wall and median side of the scapula for the posterior.. Dorso-ventral changes of the thoracic diameter and the transthoracic impedance for the total lung volume in a normal male subject were smaller at the top and larger at the bottom of the thorax.
The relationships between transthoracic impedance changes (Y) and thoracic diameter changes (X) were
Y= 3. 23 X (r =0. 95) in the upper part,
Y= 4. 00 X (r =0. 97) in the middle,
Y= 4. 68 X (r =0. 96) in the lower.
Transthoracic impedance changes per unit thoracic diameter change were also larger and grew larger towards the lower part of the thorax.

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