1. Injection of tetanus toxin into muscles of the cat's hind leg resulted in the signs of local tetanus within 18 to 24 hours.
2. When a pinna-reflex was elicited, long lasting mechanical and electrical activity occurred in the rigid muscle but not in its control.
3. Moderate stimulation of the internal capsule (CI) elicited larger and more prolonged activation of the rigid muscle than the control.
4. With strong stimulating of the CI the rigid muscle was activated by both contra- and ipsilateral stimulation. The control muscle was only activated by contralateral stimulation.
5. When the gamma-fibers were blocked selectively by 0.25% procaine solution the activation effect of CI stimulation on the rigid muscle was markedly diminished.
6. It is suggested that the gamma-motoneurons may be affected by tetanus toxin and that the rigidity of tetanus depends upon activation of both alphamotoneurons and gamma-motoneurons.

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It was demonstrated in the present paper that a heart catheter filled with air could transmit the blood pressure without distortion. The 8F double lumen catheter employed showed an almost uniform output amplitude over a range of 0 to 85cps with a phase delay of 90 degrees at 45cps. It showed no natural oscillation at the step response test and its output received no effect from catheter motion due to external force.
The arterial pressure patterns recorded in animal experiments with this air catheter showed rapid rises and smooth summits in comparison with those obtained by use of the standard catheter system. The recorded contours of the arterial pressure showed significant changes in the incisura and the form of the wave summits, when the catheter tip was moved down along the aorta from the ascending aorta to the femoral artery.

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The effect of the pressure dependency of the arterial wall elasticity upon the arterial pressure form was treated theoretically in this paper. First, the variation of rectangular pressure pattern was treated by introducing new wave equations. The arterial pressure pattern was then calculated, using an approximation of the wave form by a number of square patterns of the same duration. Because the elasticity of the arteries increases with blood pressure, the high pressure part of the systolic peak advances farther ahead of the preceding lower part as the wave propagates. As a result of calculation the variation of the pressure pattern showed a good agreement with the experimental data.

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A new method of measuring O₂ and CO₂ in expired gas by leading the sample to a glow discharge field in a vacuum tube was reported. When a gas is made to flow and is luminously discharged, an asymmetrical distribution of plus and minus charges occurs in the discharge field. Thus, when two electrodes were set in the flow path at some points proximal and distal to the discharge field the current caused by the asymmetric distribution of the charges could be measured through them. As the quantity of discharged molecules depended on the kind of gas, the current also depended on the composition of gas. Thus, the current was used to determine the concentration of the sample gas. When expired gas was introduced with air into the vacuum tube, the current was sensitive only to CO₂, while, when the sample gas was mixed with a mixture of 99.7%N₂ and 0.3%CO₂, it was sensitive to O₂ alone. When the mixing ratio of expired gas to the carrier gas was about 1: 100, a linear relation was observed between the current and the concentrations of O₂ and CO₂ in the sample gas respectively.
By use of this apparatus a simultaneous and continuous recording of O₂ and CO₂ in expired gas was made possible.

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In decerebrate and unanesthetized cats, changes in the intracellular potential of neurons in the hypoglossal nucleus following stimulation of the hypoglossal nerve were recorded.
1. Of 158 cells examined, motoneurons (94.3%), interneurons (5.7%) were distinguished by hypoglossal nerve stimulation.
2. Two groups of motoneurons responded differently in critical frequency for SD and/or IS blocking to the antidromic stimulation.
3. Sizes of the motor axons were estimated from the conduction distance and latency of antidromic invasion to each motoneuron. The diameter distribution revealed gross unimodal configuration with the peak between 3 and 5μ.
4. Some of the characters of the potential change in the “respiratory” hypoglossal motoneurons and slow fluctuations of various rhythm in others were reported.

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Intracellular recordings were made from hypoglossal motoneurons in decerebrate cats. Stimulation of the superior laryngeal nerve produced excitatory and inhibitory postsynaptic potentials, often a combination of both in the same motoneuron. These responses were polysynaptic and differed from one neuron. to another and varied widely depending upon the characteristics of the stimulation. A continuous repetition of the stimuli produced summation of the excitatory synaptic potentials leading to a short depolarization from which arose the spike discharge pattern associated with swallowing. The short depolarization was also present with the burst discharge of swallowing induced by a squirt of water into the oropharynx. It may be likely inferred that the behaviour of synaptic potentials of hypoglossal motoneurons will bear some functional relation to the pattern of the tongue movements during swallowing.

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1. Field potentials in the cerebellar cortex generated by parallel fibre stimulation were recorded and analysed with microelectrode trackings. To comprehend the sink-source relation of PSP currents in the cortical neurones, special attention was paid to compare the potentials in the cortex with different surface resistance covering over it. The surface resistance change was achieved by stopping the flow of Ringer solution over the cortex and drying the cortical surface for a few minutes.
2. Parallel fibre spike potentials and slow negative potentials in the beam of excited parallel fibres, strangely small in the cortex under Ringer solution oragar (wet state), became much larger by drying the cortex (dry state). Furthermore slow positive potentials recorded under and beside the beam in the wet state were reduced in size, markedly, and of ten reversed to slow negative potentials in the dry state. These changes were reversible and repeatable.
3. The changes had been expected from the assumption that the slow positive potential under and beside the beam of excited parallel fibres should be largelydue to EPSP currents generated directly by the excited parallel fibres in superficial dendrites of Purkinje cells and probably of interneurones (basket, stellate and Golgi cells). Relations of sink and source due to the PSP currents in the neuronal elements in the cortex and interpretations of the field potentials thereby were discussed with the aid of a simplified circuit diagram.
4. In the cerebellar cortex of the dry state, the excited parallel fibres could be detected much more precisely and extensively in depth of the molecular layer than in the wet cortex. Thus it was possible to compare the conduction velocities of deep and superficial parallel fibres. The results were discussed in connection with anatomical findings about parallel fibres in the cerebellar cortex.

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1. Responses in the cat cerebellar cortex evoked by the pontine stimulation were recorded and analysed with microelectrode trackings in the cortex. Silver ball electrodes freely attachable to the cortical surface were also used to complement the microelectrode analysis.
2. The analysis of laminar field potentials in the cerebellar cortex elicited by the pontine nucleus stimulation revealed that responses appeared at a short latency of about 1msec are due to pure mossy fibre volleys and, consequently, the nucleus sends direct mossy fibres to the cerebellar cortex.
3. The conduction velocity of ponto-cerebellar mossy fibres could be estimated to be of about 30m/sec at maximum and possibly about 10m/sec on the average, distributing rather widely when compared with that of, for instance, lateral reticular nucleus mossy fibres.
4. The mossy fibre responses to the pontine nucleus stimulation appeared most markedly in the lateral part of the cerebellar cortex on the contralateral side though sharp discriminative localization of the ponto -cerebellar projection could not be found by stimulating various foci of the nucleus and by recording from different parts of the cortex.
5. The pontine nucleus stimulation often produced the climbing fibre responses in the cerebellar cortex at a latency of 5-10msec. Much more powerful responses through climbing fibres were provoked at a latency of 5-8msec by the stimulation of the pontine tegmentum. By the experimental procedure cutting along the midline between the inferior olives on both sides, it was concluded that the climbing fibre responses set up from both the pontine nucleus and the tegmentum were mediated by the inferior olive.
6. The presumed climbing fibre responses of a short latency of 3-4msec were encountered, although seldom, by stimulating the border region between the pontine nucleus and the tegmentum, suggesting existence of some direct climbing fibres from the pontine region to the cerebellar cortex.
7. The stimulation of the cerebral motor cortex and the analyses of laminar field potentials in the cerebellar cortex ascertained that the stimulation produced the early mossy fibre responses at a latency of about 3msec and the late climbing fibre ones at a latency of about 10msec. They could be mediated by the pontine nucleus and the inferior olive respectively.

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1. Various folia of the cat cerebellum were stimulated and field potentials in the cerebellar cortex elicited trans-folially thereby were recorded and analysed by microelectrode trackings.
2. The trans-folial stimulation produced mossy fibre responses at a short latency not only in the cerebellar cortex of folia adjacent to the stimulated folium but also in that of folia far from the stimulated one.
3. With the electrophysiological methods adopted in this study, only mossy fibres were verified to connect directly folia at a distance.

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1. The origin of the seizure discharge evoked in vitro in thin sections obtained from the guinea pig dentate gyrus was studied.
2. The polymorphic layer of the gyrus was not essential for the generation of the discharge but the slice without the granule cell layer could not produce it.
3. The discharge recorded from the pial surface of the slice was composed of a train of positive spikes superposed on a negative slow wave.
4. By inserting the microelectrode into the slice, it was found that the spike took biphasic configuration at intermediate levels and reversed in polarity at the deep layer of the slice.
5. The spikes generated early and late in a discharge train changed their contour at different depths.
6. In contrast with the spike, the surface slow wave had no counterpart in the deep layer.
7. It was concluded that the spike represented the action potential generated in the granule cell body and it was conducted along the principal dendrite. This conduction was blocked at some distance from the cell body.

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1. Neuro-muscular transmission of excitation, excitatory junction potentialactivation- contraction link and tension development in the red muscle of the silver carp (Carassius auratus) were investigated and the results were compared with those of the white muscle and with the frog slow fibres.
2. Miniature excitatory junction potentials (mejps) could be recorded from the postsynaptic membrane. The mean amplitude was 0.45mV and the mean interval was 421msec. The histograms of the mejp amplitudes and of intervals were skew. The mejps and excitatory junction potentials (ejps) produced by nerve stimulation were probably due to release of acetylcholine from the nerve terminals.
3. The observation that ejps were recorded in many parts of the same muscle fibre in response to nerve stimulation suggested a diffuse innervation of the muscle fibre.
4. The equilibrium potentials of the ejps recorded in red muscle ranged between -30 and -35mV.
5. Excess calcium increased the effective resistance of the postsynaptic membrane and increased the amplitude of the mejps and ejps. Excess magnesium did not change the membrane resistance but reduced the frequency of the mejps and the amplitude of the ejps.
6. The delay in generation of ejp after the peak of the nerve action potential was 0.53msec.
7. The relation between the membrane potential and tension development was determined. The critical level of membrane depolarization required to induce tension development was 60mV and this level was exceeded by the amplitude of the ejp.

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