A model of neural networks in the vertebrate retina was constructed on the basis of the neurophysiological data, its spatio-temporal characteristics were calculated with a digital computer, and compared them with the psycho-physical data on the human vision. This model consists of three neuronlayers-input (recepter cell) layer, intermediate layer and output (ganglion cell) layer, which are connected each others in series (temporally) and in parallel (spatially), so that receptive fields are constructed. An analysis of these networks was carried out with matrix calculus in parallel connections and Mikusinsky's operational calculus in series connections. Input-output relations for simple spatio-temporal input stimuli were obtained.
The results show quantitatively a good agreement with the fundamental psychophysical data of Mach and Broca-Sulzer phenomena, and those of spatial and temporal frequency responses of the human vision, when a time constant and a threshold level of inhibitory connections are made higher than that of excitatory connections in the intermediate stage.

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In these several years, histological studies at cellular level have been growing as the result of development in fluorometric technique. It is, however, rather difficult to carry out comparative, quantitative fluorometry for the sake of data processing largely relying upon photographic and biochemical analyses.
In this paper, 2 types of methods, the ideal filter method and the correlation method, are discussed with special reference to overcoming the difficulty involved in measurement of a very weak fluorescent light in the tissue. As the theoretical consequence the correlation method is shown to be effective in measuring a very weak fluorescence of a sample under microscope. The principle of the correlation method is as follows : The fluorescent light emanating from the sample being chopped, the chopped signal is detected and amplified by a photomultiplier. On the other hand, the reference signal with the same frequency is generated synchronously. The amplified signal is multiplied by the reference signal continuously. The multiplied output is integrated. Finally the intensity of the fluorescence is read on an ammeter or voltmeter. On the basis of the principle described above the authors devised an electrical fluorophotometer, which has been proved to function effectively through several experiments.
The present series of experiments has clarified that the difference in intensity of fluorescence in tissue is determined corresponding to the difference in serotonin (5-HT) concentration, and that the fluorescence in the tissue is composed of 2 components, the autofluorescence and the singular fluorescence that decays exponentially when the sample is continuously exposed to ultraviolet ray. It has been also made clear that the time constant of the decreasing fluorescence depends upon the nature of the substance.
This photometer possesses the aperture of 0.7 mm, and is set up on the position of the microscope camera.

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Fetal heart rate is known as one of the best representations of the fetal situations in labor. The heart rate is counted by means of FECG or FPCG obtained from the maternal abdominal wall or direct ECG from the fetal scalp after rupture of the amnionic sac. However, these methods are not satisfactory by the reasons of poor signal to noise ratio, difficulty in continuous monitoring, and so on. Accordingly, we applied the radiotelemetry to measurement of FHR, in which an adequate size transmitter combined with electrodes was inserted into the uterine space. The direct FECG was transmitted throughout all stages of labor and received by a commercial short wave radio receiver placed near by. And ECG of the newborn baby was also taken from the axilla with ease by a clip electrode-transmitter consisting a clip electrode for adult limb lead and a small transmitter. The carrier frequency was chosen at about 6 Mc/s and the amplitude was modulated by the signal. The size and the form of the transmitter were determined to allow easy insertion to uterine space, complete contact with the amnionic sac and easy exchange of the battery, and not to behave as a foreign body and not to being exhausted by delivery. After construction on the board of printed wiring, the transmitter was molded by silicon rubber. to prevent from injuring the body and to be insulated from the tissues. The total weight and volume were 15 g and 9 cm³, respectively. Drain current was 200, uA with the receiving range of about 1.5 meter. ECGs of six fetuses including three cases of cesarean section were investigated throughout labor and delivery. Especially interesting results were obtained of FHRs before and after rupture of the amnionic sac, labor, delivery and ligation of the umbilical cord and during cesarean section.

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