Antidromic olfactory tract stimulation in the rabbit evoked a response which was composed of an initial positive-negative spike, a second negative component and a slow negative wave in shallow layers. In deeper layers the two early components were followed by an initial negative spike and a slow positive wave, while the slow negative wave increased in size.
The two early components had almost the same refractoriness; absolute refractory period was 4-6msec. and relative refractory period was in the range of 30-60msec. The slow positive wave had about 50msec. refractoriness, while the slow negative wave had no definite refractoriness, but it was of a summating nature.
The deep initial spike was an antidromic volley in mitral cell axons, and it became through the mitral cell bodies the shallower initial positive-negative spike, which was propagated at the conduction rate of about 0.5m/sec. towards the apical dendrites.
From the effects of asphyxia, topical curarization, and the behavior to repetitive stimulation of the anterior commissure and of the olfactory tract itself, the second negative component was revealed as activities of abundant basal dendrites activated synaptically through the recurrent axon collaterals of the mitral cells. During observation on unit discharges, double discharges were sometimes found. The second spike of the double discharge behaved like the second negative component in some respects and appeared to be elicited synaptically through the recurrent axon collateral of a mitral cell. This finding gives a favorable support for the above interpretation of the second negative component. It was found, moreover, that the deep slow positive wave was the condensed ‘source’ of the second negative component of the whole bulb cortex.
Finally, the slow negative wave is considered as the activity of a large number of internal granular cells because of its similarity to the anterior commissure response. In addition, the depth relationship and interaction among the bulb surface response, the olfactory tract response and the anterior commissure response were examined.

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With strong illumination electroretinograms were recorded in mammals (cat, rabbit and guinea pig), birds (pigeon and chicken) and cold-blooded vertebrates (tortoise, bullfrog and lamprey). All examined animals except the lamprey, showed clearly multiple wavelets comparable with the oscillatory potential in the human electroretinogram: the wavelets were superimposed on the slow waves of the electroretinogram, and spaced at a nearly equal interval with little reference to the intensity of stimulating light. The main features of the wavelets seemed to be in common with those of the oscillatory potential in the human electroretinogram. The period of the oscillatory potential was approximately 4.5, 4.5, 10, 8, 10, 20 and 45 milliseconds respectively for the cat, rabbit, guinea pig, pigeon, chicken, tortoise and bullfrog retinae.
The origin of the oscillatory potential was discussed. Findings from this paper, in conjunction with other lines of evidence, indicate that the oscillatory potential is located in the bipolar cell layer or in the vicinity of this layer.
It is suggested that the oscillatory potential differs in the generation mechanism from the classical electroretinogram, and may actually be a distinct component of the electroretinogram.

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In order to investigate inhibition of vasomotor and sudomotor sympathetic activities by the stimulation of the limbic system, experiments have been conducted with fifty-five bilaterally vagotomized cats, recording blood pressureskin potential. Effects of brain stimulation upon parasympathetic and cholinergic sympathetic activities were prevented by atropinization.
1. Stimulation of the hippocampus and the fornix proper yielded depression blood pressure and inhibitory response of skin potential. The depression not caused to disappear by atropinization.
2. Stimulation of the amygdala and the lateral preoptic area produced depression of blood pressure without associating inhibitory response of skin potential. Facilitatory response of skin potential was elicited with strong stimulation. depression was not affected by intravenous administration of atropine.
On the basis of these experimental results, it was suggested that the areas to inhibit the sympathetic activity in the limbic system fall into two groups as far as vasomotor and sudomotor activities are concerned, and that inhibition of the sympathetic activity is not always diffusely observed in many of the effector organs.

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In order to analyze inhibitory effect of the bulbar reticular formation upon the sudomotor activity, experiments were performed with 25 adult cats immobilized with Flaxedil. Response patterns of skin potential due to brain stimulation were classified into three types; facilitatory, inhibitory and mixed.
1. Inhibitory response was elicited from the bulbar ventromedial reticular formation. From region surrounding the inhibitory area, mixed response was evoked. Facilitatory response was elicited from the bulbar lateral reticular formation.
2. Inhibitory response due to bulbar stimulation became marked with increase in strength, pulse duration or frequency. The strength-duration curve for threshold of a 50% decrease in amplitude of the GSR was a rectangular hyperbola and chronaxie calculated from the vt-t curve was 0.3msec.
3. The stimulation of restricted area surrounding the inhibitory area, produced inhibitory response at frequencies above 150/sec. In this area, however, response frequently appeared in the form of facilitation at frequencies below 10/sec. At frequencies between 10 and 150/sec., mixed response was elicited.
4. Analysis of post-inhibitory rebound following bulbar stimulation, revealed that there exists an optimum duration of brain stimulation which causes a maximum of rebound: 5 seconds. It was also found that there exists a close parallelism between amplitude of rebound and degree of inhibition. Contribution of IPSP to initiation of post-inhibitory rebound was suggested.

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It has been demonstrated that the early toxic symptoms due to endotoxin in rabbits, such as depression, dyspnea and diarrhea were due to central autonomic disturbances and could be sedated by antipyretics. The late stage of intoxication was characterized by hepatic glycogen depletion due to enhanced glycogen utilization and relative adrenocortical insufficiency. Hypoglycemia, hypothermia and arterial hypotension which could not be influenced by antipyretics ensued. Thus dual mechanisms of endotoxin intoxication have been postulated: the one is the central autonomic disturbances related to the activation of the febrile mechanism and the other is the metabolic disturbances leading to carbohydrate depletion. The latter has been discussed in relation to the uptake of endotoxin in hepatic reticuloendothelial cells.
The dyspnea, the most characteristic toxic manifestation in rabbits were found to be due to epinephrine discharge which is prone to occur in this timid species.Even respiratory disturbances leading to early deaths could occur. In adrenalectomized rabbits, although the dyspnea was absent, a marked tendency to vagotonia leading to an irreversible depressor reflex or a marked depletion of carbohydrate store determined their extreme susceptibility to endotoxin.

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Using curarized cats under artificial respiration, the following observations were made.
1. In the dark room, 3-7/sec regular sinusoidal waves spontaneously appeared in the lateral geniculate body, optic tract, and in some cases in the cortical visual area, sometimes immediately after, and mostly from 30-minutes to several hours after the insertion of the depth electrodes.
2. These waves were blocked by illumination abruptly, and after the cessation of illumination, with latency of less than 1-3 sec, sinusoidal waves reappeared. In the pretectal area, these waves were hardly observed. Sometimes under illumination, bright rhythm of higher frequency appeared.
3. These waves appeared easily, especially during nitrous oxide gas inhalation, or after the administration of ethyl alcohol and, though it was less frequent, after the administration of small dose of pentobarbital.
4. These waves were not abolished after the unilateral cutting of the optic tract (ipsilateral or contralateral) or one side enucleation of the eye ball, but waxing and waning phenomenon was diminished after one side cutting. After cutting of the bilateral optic nerves, 3-7/sec synchronized waves did not appear.
5. These waves were hardly influenced by reticular or hypothalamic stimulation, by peripheral nerve and noxious stimulation. Stronger stimulation, suppressed these waves with relatively longer latent period (1-2 sec) and desynchronized to the low voltage fast activity.
6. Localized activation of the visual cortex by high frequency electrical stimulation of the optic tract, lateral geniculate body and pretectal area or by photic stimulation was considerably difficult in contrast to the relative easiness of localized activation in the auditory cortex.
7. In the preparation with both optic nerves cut, though photosensitive synchronized waves did not appear, electrical stimulation of the optic tract and lateral geniculate body easily elicited in the lateral geniculate body and visual cortex ca.10/sec waves.
Stronger stimulation of the reticular formation also produced the similar waves in the lateral geniculate body. From these findings the different characteristics of the electrical activity in the visual system compared to other cortical and subcortical areas were discussed.
These results were reported in the 133rd Meeting of Tokyo Association of Japan Physiological Society in October 10, 1959 and in the 11th Annual Meeting of the Japan EEG Society in 1960.The authors wish to express their sincere thanks to Prof. T. TOKIZANE for his valuable suggestions, and to Miss M. TAKAHASHI for preparing histological sections.

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Adrenocortical activity of rats kept at a high ambient temperature of 32°C. for approximately 3 weeks was studied.
1. Adrenal weight, adrenal contents of cholesterol, ascorbic acid and corticosterone in rats kept at 32°C. did not depart from the values obtained in those kept at 20°C. Corticosterone content in the blood plasma of rats at 32°C. was slightly less than that in rats at 20°C., but the difference was not statistically significant.
2. In both groups of rats adrenal ascorbic acid concentration decreased to similar extent after administrations of epinephrine or ACTH.
3. The increase in corticosterone content in the adrenal and blood plasma provoked by epinephrine or ACTH injections was significantly greater in rats at 20°C. than in those at 32°C.
4. The reduced adrenal response to exogenous ACTH in rats kept at 32°C. was also demonstrated in hypophysectomized rats.

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Rabbits have been shown to resist sodium chloride restriction even after adrenalectomy. The renal mechanisms of reabsorbing sodium chloride and sodium bicarbonate are well developed in this animal species and do not necessitate mineralocorticoids except in cases of forced sodium loss, such as due to starvation or thiazide medication. There exists a series of marked species differences in the development of these renal tubular mechanisms in the order of rabbits, rats, and dogs. This is reflected in the species difference in the derangement of mineral metabolism after adrenalectomy.

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1. Aconitine-induced fibrillation was studied on the right atrium isolated from a young rabbit, and the electrical activity from two fibers was traced simultaneously in order to clarify the mechanism of the appearance and termination of the fibrillation.
2. The administration of aconitine (0.8-1.5×10^-6) was followed first by an acceleration and fluttering of the atrial activity, and next by the formation of local blocks and disturbance of the spread of sinus rhythm. An irregular fluctuation and increased dispersion in size of the resting potential were produced resulting in nonsynchronized local or abortive activities of the cells and a temporal fibrillation which finally ceased.
3. Reintroduction of the normal solution induced the formation of one or more ectopic pace-makers.The activity was intermittent at first, waxing and waning, and occurred one after another or one with another. These states gradually developed into a typical fibrillation which continued a few hours.
4. During the fibrillation, no definite circus movement was observable mainly due to the uninterrupted variation in activity of each fiber and the frequent occurrence of pace-maker shift.
5. In the course of recovery from the fibrillation, synchronism in activity of each fiber, full magnitude of the action potentials, and their uniformity in shape and rhythm were gradually restored with disappearance of local blocks.
6. It was estimated that the formation of local blocks and ectopic pace-makers might be principal factors in the development of atrial fibrillation.

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By using a servo-mechanical system the potential difference between the inner and the outer surfaces of a frog skin was clamped at zero mV and the short-circuit current was measured precisely.The following results were obtained:
1. The short-circuit current is thermo-reversible between about 3° and 22°. This is also proved when an inhibitor is applied to the frog skin.
2. Between 6°C and 20°C the short-circuit current is almost equal to the net sodium transport at each temperature. This is proved by using the double labelling method.
3. Based upon the thermodynamics of irreversible process the short-circuit current is deduced to be the change of Gibbs free energy.
4. The short-circuit current is so influenced by the temperature that the curve log I_s/I_s20-1/T consists of two parts:the one for the normal and the other for low temperature.The point of intersection lies between 10°C and 15°C.
5. The temperature coefficient of the short-circuit current at low temperature is larger than that in the normal temperature region.
6 Some inhibitors decrease the short-circuit current in the normal as well as in the low temperature regions.They do not markedly effect the temperature coefficient in the normal temperature region, but in the low temperature region they have a marked effect on the temperature coefficient.
7. The electrical conductance was measured.The curve C-t also consists of two parts: the normal and the low temperature regions. The boundary lies between 10°C and 15°C generally.
8. At least two or more mechanisms, including enzymatic action, are concerned with the Na-active transport in the frog skin.

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