1. Mechanical characteristics of the toad blood vessels under different temperatures were investigated with the use of the universal tensile testing instrument.
2. The amplitude of tension generated by cyclic stretches of the aorta at 41% stretched state was constant throughout the temperatures between 3-40°C, while that induced at 100% stretched state increased with decrease of temperature. In both cases, however, the lower tension levels lowered as temperature fell.
3. Over 40-50°C, a marked increase of the tension amplitude was observed with distinct elevation of the upper tension level in both cases of 41% and 100% stretched states.
4. In the tempreature dependency of mechanical characteristics, the elastin dominant vessel treated with formic acid coincided well with the wall of vessel at 41% stretched state, while the tendon, aponeurosis plantalis, was in accord with the vessel at 100% stretched state. However, the marked increase of tension at temperatures over 50°C was never observed in the digested aorta, supporting a view that it depends on the thermal denature of collagen.
5. Hysteresis loops of the aorta and vena abdominalis became small at normal temperature and large at low (2-5°C) and high (40-42°C) temperatures. With the tendon and formic acid treated vessels, the hysteresis loops also tended to enlarge at low temperatures (2-5°C). However, over 50°C merely the tendon showed a great deal of increase in the loop.
6. Stress-relaxation curves of the aorta and vena abdominalis declined with a rise of temperature up to 40°C, but no detectable difference between their temperature dependencies of distribution function was observed. The relaxation modulus increased markedly at high temperatures over 50°C, showing distribution function of distinct box-shape.

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The activity patterns (response amplitude-frequency diagram) of ten anesthetized and eleven unanesthetized rabbits brain evoked by repetitive flash stimulation of varying frequencies (1-15/sec) were observed with respect to the stimulating frequency in the lateral geniculate body (GL), optic radiation* (OR), midbrain reticular formation (RF), Pulvinar*(Pul), superior colliculus (CS) and visual (Vc) and limbic cortex* (Lc), wherein those in the starred sites were observed under unanesthetized situation only.
The activities in each of the specific and nonspecific structures presented characteristic patterns and in Lc, too. In GL and OR, the initial potential with short duration (A potential) was augmented at 4.5-6/sec flash stimulation and the slow component (C potential) was enhanced at 2-3.5/sec which suggests cyclic activity changes at these frequencies. On the contrary, it was demonstrated that the activities of RF were characterized by 1 and 4/sec under anesthetized state and by vast augmentation at less than 5/sec under unanesthetized state, though no conspicuous cyclic property. In the Lc, an independent cyclic property from the above specific systems was observed. These observations were confirmed by the repetitive electrical stimulation to GL or RF, suggesting that the augmenting and recruiting-like responses play a rôle at least in part.
The activity patterns associated mainly with the specific activity were not affected by anesthetic condition, while the activities or the potential components related closely with RF were most affected by anesthesia.

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The disappearance of thyroxine (T₄) from the blood and oxygen consumption of thyroidectomized rabbits were studied with the following results:
1. An acceleration of blood T₄ disappearance rate occurred after a lapse of time following T₄ injection at doses over 2.0μg/100g body weight.
2. This acceleration appeared the sooner in the animals injected with the larger dose of T₄
3. The simultaneous study on the oxygen consumption and T₄ disappearance indicated that the acceleration of the blood T₄ disappearance rate became evident after the metabolic rate was increased.
4. From the analysis of the nature of the disappearance curve of T₄ in the blood, it was indicated that the accumulation of injected T₄ in peripheral tissues caused an increase of metabolic activity, which accelerated the T₄ disappearance rate by elevating diffusion and/or degradation rates of T₄.

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1. The peak-to-peak amplitude of the H-wave of the gastrocnemius muscle was inhibited in inspiration, in lying on the recorded side and in an ankle extension, while the magnitude of the mechanical response was augmented.
2. The form of H-wave is not tetra-phasic, but is very often superimposed by a small notch suggesting that the H-wave is composed of two components.
3. The long latency component has a lower threshold to stimulation of the dorsal root filament and potentiated by tetanic stimulation.
4. The short latency component has a lower threshold to stimulation of the ventral root filament and augmented during voluntary contraction.
5. Some muscular units have a same latency with the H-wave and others fire coincident with the appearance of the notch.
6. The short and long latency component is the kinetic and tonic activities, respectively.
7. The H-wave is the vector summation of these two activities, so that the peak-to-peak amplitude can not be a measure of the machanical response.
8. H-waves in various state of muscular activities were discussed from the standpoint of tonic and kinetic activities.

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1. The cardiopneumatic volume change in the lung (IP) and that in the body (EP) were measured separately by using a dual plethysmographic method. An averaging technique was adopted for cancelling noises arising in-and outside of the plethysmographs.
2. Inspiratory gas flow of 2 to 9ml was observed at the cardiac systole, and almost the same amount of volume change was observed in the body.
3. There were considerable individual variations in IP and EP, but the time relation between those curves and ECG was rather constant among different individuals.
4. The pulsations of the chest and abdominal walls were also measured simultaneously with IP and EP. They showed an inward movement at the systole, but the commencement of its downward movement occurred earlier by about 50 msec than the change of EP.
5. The cardiopneumatic change in the airflow velocity was measured through a pneumotachograph, and the output was converted into a volume change through an electronic integrator. A close resemblance was seen between the integrated patterns and those of IP and EP.
6. The amplitude of IP, EP and the chest wall pulsation increased sigmoidally with the inflation of the lung. On the other hand, when the airway was obstructed, the pulsations of IP and EP decreased while those of the chest wall showed a slight increase.
7. From the observations mentioned above the following conclusion was derived. When the heart contracts, the thoracic and abdominal walls move inward, and at the same time the blood volume in the thorax is reduced. From the time relation of both changes, however, it seems to be clear that in the normal lung the former change is not caused by the negative pressure generated by the latter change but caused directly by the heart or deformation of pericardium. The origin of the cardiopneumatic change, i. e. IP and EP, therefore, may be ascribed to the difference of the above two volume changes.

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Fifty human sub jects have been kept in an underground bunker in conditions of continuous illumination, each in complete isolation and without any time-telling device. Rectal temperature was recorded continuously by means of an electric thermometer, and urine samples, collected in intervals of the subjects own choice, were analyzed for excretion of water, sodium, calcium and potassium. Several systems of electric contacts served to survey the subjects general activities. All subjects showed free-running circadian rhythms, the average periods of wakefulness and sleep ranging from 23.9 to 50.0 hours. 36 subjects remained internally synchronized during the whole experiment. In 5 cases, the rhythm of activity and the rhythms of vegetative functions were synchronized in a 1: 2-ratio for parts of the experiment. 9 subjects showed different circadian frequencies in activity and in body temperature; in two of these subjects, desynchronization started immediately after being enclosed in the bunker, in the remaining 7 subjects after 9 to 23 days of confinement.

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1. The reflex responses of the distention of the gall bladder or the biliary duct on the movements of the stomach, small intestine and proximal colon were investigated in the dog anesthetized with pentobarbital sodium or in the spinal dog.
2. The distention of the gall bladder with the pressure of 50 to 160mmHg exerted an inhibitory effect on the movements of the stomach and small intestine and the excitatory or the inhibitory response on the colonic movements.
In dogs whose spinal cord was transected between the 2nd and 3rd thoracic segments the inhibitory response was also obtained.
3. In most cases, after bilateral sectioning of the thoracic splanchnic nerves the inhibitory response was not completely abolished. After the 1st lumbar through the 5th lumbar splanchnic nerves were bilaterally sectioned in addition, the inhibitory response was completely abolished.
After sectioning of the vagus nerves the excitatory response of the colonic movements was replaced by the inhibitory one.
4.After severing the 4th thoracic through the 13th thoracic posterior roots the inhibitory response was also completely abolished.
5. It is concluded from the results that the afferent pathways responsible for the inhibitory reflex on the movements of the stomach and small intestine elicited by the distention of the gall bladder are the thoracic and the lumbar splanchnic nerves and the posterior roots of the 4th thoracic to the 13th thoracic segment, while the efferent inhibitory pathways are the thoracic and lumbar splanchnic nerves.
6. The distention of the biliary ducts caused an excitatory or inhibitory effect on the gastric movements, while it always produced the inhibitory effect on the small intestine. After the sectioning of both vagi the excitatory effect on the stomach was reversed to the inhibitory one.

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The activity of single neurones in the hypothalamus of ovariectomized estrogen-treated cats immobilized by gallamine triethiodide was recorded by means of steel microelectrodes with simultaneous observation of presigmoidal EEG. Alterations in the firing rates of single units were analyzed during and after vaginal stimulation during anestrus and estrus animal. Unit responses to LH (3 Armour units) and oxytocin (0.3 U.) injection were also observed both at the anestrous and estrous states.
1. In the VMH of the hypothalamus, neurones were found which responded to LH administration by a long lasting decrease in unit firing rate with latency of 10-20 minutes in estrus and anestrus. Some ARC neurones showed an increase during estrus, and also an increase to a less degree in anestrus. Also, in the AHA some neurones were found which increased in discharge rate, but the change was less remarkable. The changes in the LHA or the PHY neurones were not clear.
2. Oxytocin sensitive neurones discrete from LH sensitive neurones were found in the hypothalamus. The unit discharge rate increased or decreased with latency of 40-80 seconds lasting for several minutes according to electrode location and to the phase of the sexual cycle.
The VMH neuronal activity showed a slight facilitation in estrus but a strong inhibition in anestrus. In the ventromedial part of the LHA and the AHA the unitary activity was inhibited by oxytocin during estrus, but facilitated in anestrus. Distribution of LHA responsive neurones in the dorsolateral portion of LHA was quite disperse.
3. The VMH neurones discharged in accordance with the change in presigmoidal EEG pattern. During vaginal stimulation in estrus the VMH neural. activity was inhibited or unchanged but after cessation of the stimulation it showed a transient facilitation with simultaneous appearance of spindle bursts. in presigmoidal EEG. A marked inhibition followed which lasted for more than 20 minutes, with cortical EEG spindle bursts intermingled with arousal waves.
Some AHA neurones in estrus showed a marked facilitation during vaginal stimulation, but no after-reaction was observed.
Most neurones in the ventromedial part of the LHA, both in estrus and anestrus, showed increased firing activity during vaginal stimulation. After the cessation of stimulation the activity began to decline simultaneously with the appearance of spindle bursts in the presigmoidal EEG, and after about 10 minutes the initial state was restored. Long-term alteration, such as that seen in the VMH, was not observed.
During estrus the neurones in the dorsolateral part of the LHA showed a transient increase in discharge activity after vaginal stimulation independent of the changes in presigmoidal EEG activity. In anestrus these neurones did not respond to vaginal stimulation.
Stimulation by other means such as pinching or touching, had an effect similar to vaginal stimulation, except that no after-reaction occurred.

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