1. A large amount of magnesium was necessary for the clearing response of actomyosin and its degree increased and its duration prolonged with increasing the concentrations of magnesium and ATP.
2. A small amount of magnesium was necessary for the process of the superprecipitation.
3. Calcium inhibited the clearing response depending on its concentration and by it accelerated the process of the superprecipitation.
4. The inhibitory effect of calcium on the clearing response was in linear relation to the logarithm of the concentration of calcium. This effect of calcium was to a large extent dependent on the conditions of the reaction.
5. Calcium, strontium or barium inhibited the clearing response. On the other hand, the addition of magnesium, manganese or bivalent iron led markedly to the clearing response. The shorter the ionic radius of bivalent cation was, the more remarkable the clearing response was.
6. In the presence of magnesium, other bivalent cations inhibited the clearing response and accelerated the process of the superprecipitation. The degree of these effects was dependent on the ionic radius of bivalent cation, and was maximum at 0.95×10^-8cm.

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1. Increment of ionic strength made the clearing response remarkable. Calcium inhibited the clearing response at high ionic strength, whereas magnesium accelerated it. Furthermore, in the presence of magnesium the system of actomyosin and ATP became sensitive to the change of the conditions at a certain ionic strength. EDTA inhibited both the clearing response and the superprecipitation.
2. Dioxane and ethanol accelerated the superprecipitation by inhibiting the clearing response in the presence of magnesium. On the other hand, in the absence of magnesium dioxane and ethanol inhibited both markedly the clearing response and slightly the superprecipitation. Furthermore, the addition of urea or guanidine-HCl led markedly to the clearing response even in the absence of magnesium.
3. A small amount of p-chloromercuribenzoate inhibited the clearing response, whereas accelerated the superprecipitation in the absence or presence of magnesium. Its large amount inhibited both.
4. ITP was able to be replaced with ATP for both the clearing response and the superprecipitation, whereas PPi was not able. Its action of ITP was not so powerful as ATP.

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1. In decorticate monkeys, location of receptor for the righting reflexes acting upon the body was examined.
2. When lying in the lateral position, an electrical stimulation of the uppermost splanchnic nerve evoked stereotyped changes in position of all four limbs, identical in pattern with the righting reflexes acting upon the body, which were executed by reciprocal responses of the antagonistic muscles of four limbs.
3. The same responses of the skeletal muscles were also induced by an electrical stimulation of the mesentery and of the thoracic and cervical sympathetic trunks.
4. Moreover, the same responses of the skeletal muscles were evoked by an electrical stimulation of the proximal cut end of the splanchnic nerve, whereas no response was caused by stimulation of its distal end.
5. From these results, it was concluded that the receptors for the righting reflexes acting upon the body lie in the mesentery.
6. The conclusion obtained from our experiments is supported by the body reflexes acting upon the body in spinal men described by POLLOCK and his coworkers which are readily evoked while immersed in water in a swimming pool.

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1. The stimulation of the thoracic or cervical vagus usually results in excitation of the jejunal movements followed by the inhibitory effect. In the present experiments the cause of the inhibitory response was investigated by the application of various agents affecting the nervous structures in the intestinal wall.
2. The movements of the jejunum, 15cm long and severed from the rest of the intestine, were recorded using the balloon method on dogs anesthetized with urethane and morphine or pentobarbital sodium.
3. The weak stimulation of the vagus caused, in general, the excitatory response only; on the other hand, the strong stimulation produced an initial excitation followed by inhibition.
4. After the application of 0.4% cocaine solution into the jejunal lumen for 3min, the response to the strong stimulation of the vagus reversed to excitatory. It may be considered that cocaine could paralyse the inhibitory neurone in the myenteric plexus of the intestinal wall.
5. The reverse phenomenon similar to that elicited by the application of cocaine was obtained also after the intravenous injection of tubocurarine or nicotine, but it was difficult with the intravenous injection of hexamethonium bromide. It may be supposed that ganglion-blocking agents such as nicotine and tubocurarine could affect the synapses of the inhibitory neurones more powerfully than those of the excitatory ones.
6. After atropinization the excitatory response of the vagus reversed to the inhibitory one.
7. Provided that there are at least two kinds of the effector neurones in the myenteric plexus, the excitatory and inhibitory neurones, and that these neurones connect synaptically with the presynaptic fibers in the vagus, it may be considered that the results described above could be easily explained.

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1. By the use of small strips excised from the inner wall of the ventricle of Dolabella, effects of some cations on the potassium and caffeine contractures, in addition to the relation between the membrane potential and the height of potassium contracture, were examined.
2. The relation between the logarithm of external potassium concentration and the membrane potential was linear in high potassium concentration, but the membrane depolarized in potassium-free solution.
3. In a high potassium concentration the height of spontaneous contractions reduced, accompanying reductions in the amplitude and duration of the action potential.
4. Potassium contractures were induced in the solution containing more than 40 mM of potassium chloride, and the relation between potassium concentration and the height of contracture was similar to that in vertebrate muscles.
5. While no contracture was induced in calcium-free potassium solutions, caffeine contracture was induced in calcium-free solutions.
6. Antagonism between sodium and calcium in the potassium contracture was not so remarkable as expected from the ratio of [Ca]/[Na]² in the external fluid, while there was a noticeable antagonism between calcium and magnesium.

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The role of the neurohypophysis in ACTH release mechanism was investigated in the rat by measuring changes in blood ACTH levels under various kinds of stress. A remarkable increase in blood ACTH following repeated pain stimuli of 1 second duration on the paws or injection of synthetic lysine vasopressin, 400mU./100g. i. p. or i. v., was seen in the normal intact or the sham-operated rats, while it was absent or considerably reduced 1 week after the removal of the pituitary neural lobe. Prolonged pain or laparotomy induced a marked rise in blood ACTH both in the control and the neurohypophysectomized rats, but the elevation of blood ACTH was significantly less in extent in the absence of the neural lobe. Intraperitoneal injection of histamine induced a moderate rise in blood ACTH to the same extent both in the control and the neurohypophysectomized rats. The extract of the pituitary neural lobe of the rat, in a dose of 400 milli pressor units of lysine vasopressin, induced a considerable rise in blood ACTH regardless presence or absence of the neural lobe, but was not effective in the hypophysectomized rats. Since the ablation of the neural lobe resulted in a near-complete abolishment of vasopressin's corticotropic effect, the increase in blood ACTH following injection of the neurohypophysial extract may be due to CRF stored in the neural lobe. Blood supply to the adenohypophysis was not impaired, but rather increased 1 week after the removal of the neural lobe.

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Detailed relations between the electric conductivity of the skin and sweating were investigated by simultaneous, continuous recordings of skin conductivity and sweat rate on a pen-writing oscillograph in healthy sub jects and patients with anhidrosis. Evidence is presented that skin conductivity is mainly a function of sweating. The specific electric conductivity of the paste or solution used for the skin electrodes affected largely the patterns of fluctuations of skin conductivity, whereas the kind of electrolyte in the solution had little influence on it. Characteristic changes of conductivity of the palmar skin were noted. The movement of the electrolyte ions into sweat-ducts appears to be the most important factor affecting variations of skin conductivity with sweating. Possible changes in size of sweat-ducts in association with the activity of sweat glands are assumed also to participate in these mechanisms. Various patterns of variations of skin conductivity are discussed on the basis of these assumptions.

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Effects of conditioning stimulation of the cerebral cortex upon excitability of the terminals of the optic tract (OT) were examined in unanesthetized cats with immobilization. The cortical stimulation was made with a single shock or repetitive pulses at 100-300/sec.
1. The antidromically conducted action potential of the OT, produced by stimulation of the OT terminals within the lateral geniculate body (LGB) and recorded from the optic chiasma, was enhanced following the cortical conditioning stimulation. This facilitatory effect appeared with a latency not less than 10 msec, reached the maximum at about 60-90 msec and continued sometimes beyond 400 msec. The facilitation increased with increasing the number of pulses for the cortical conditioning stimulation and was seen with varying the intensity of the testing stimulation in a wide range.
2. The action potential of the terminals of the OT, produced by stimulation of the optic chiasma and recorded from within the LGB, was suppressed by cortical conditioning stimulation. The time course of this suppression was about the same as that of facilitation of the antidromic response of the OT.
3. Combining the above-mentioned findings, it was concluded that the effects of cortical stimulation were manifestation of the presynaptic inhibition in the LGB.
4. In the cortex ipsilateral to the OT terminals examined, a posterior half of the lateral gyrus was the area from which facilitation of the antidromic OT response was most easily elicited. Next to this, stimulation of the middle supra-and ectosylvian gyri was effective. The active spots were found distributed also on the contralateral cortex in about the same way as in the ipsilateral side.
5. Nembutal was effective to suppress the cortical facilitation of the antidromic OT response. Attempts to see the effects of picrotoxin failed to yield conclusive evidence.

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