The reduction of membrane potential of frog sartorius muscle fibers which was produced by the removal of Ca ions has been compared with the depolarization due to high K. The change of membrane potential and the passive fluxes of K ions have primarily been investigated. At the same level of depolarization, K rich or Ca free condition has each pattern of the movements of K ions. This discrepancy can probably be explained by the difference in the membrane structure resulting from the high K or Ca free condition. Although it is said that K ions act on the membrane as ionic activity and Ca ions as the regulator of the normal structure of the cell membrane, both are the constituents which maintain the membrane structure in the respective ways. However, the valency of each ion may be the most important factor for the membrane structure by which the resting or action potential can be produced.

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Experiments have been carried out in an attempt to determine the relationship between the membrane resting potential and potassium ions by increasing the K concentration or adding Ca. The results give some suggestion to the problem of electrolyte distribution in the muscle fibers. The physical phenomena taking place in the membrane such as membrane potential or flux may be the function of the membrane structure. The ionic distribution is probably not a cause for membrane phenomena but a result of the change in membrane structure.

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Several data on the growth of Myc. lepraemurium in the experimental mouse and rat by inoculation through subcutaneous, intraperitoneal, intracerebral, intratesticular, and intravenous routes, respectively, have been already reported. The factors influencing the susceptibility of mice, especially the kinds of mouse strains, to the bacilli were vigorously studied by several investigators in order to determine the optimal conditions for the screening test of chemical agents against murine leprosy using experimental mice. However, there have been no reports, so far, concerning the growth of Myc. lepraemurium in mice transplanted with malignant tumor. The present paper reports the investigation of a relationship between murine leprosy and Ehrlich ascites tumor inoculated into the mice by the same routes at a different or at the same time.

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The electrical membrane characteristics and activity of an amphibian sympathetic neuron and the mode of its synaptic transmission studied with intracellular microelectrodes have previously been reported by Nishi and Koketsu (1960). Further analysis has been carried out on the neurons of the lumbar sympathetic ganglion of toads. The present paper deals with the electrical responses of two different sympathetic neurons, one of which protrudes a B fiber as its axon (sB neuron) and the other a C fiber (sC neuron), and the mode of the presynaptic innervations of these two neurons. The authors found that the electrical responses of the two neurons are characteristically different from each other, especially in the configurations of their after-potentials, and in the manner of the separation of their antidromic responses under the hyperpolarization of the soma membranes. The modes of presynaptic innervations of these two neurons were also found to be very specific the two postganglionic elements receive innervation independently from the preganglionic neurons of the same types, and no interconnection was found between the pre- and post-ganglionic neurons of the different types. Such an innervation pattern is characteristically different from that of the mammalian sympathetic nervous system. In this system it has long been known that the postganglionic elements are innervated exclusively by the medullated preganglionic elements; the B fibers.

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A remarkable change in histological and pathological fields has been brought about by the excellent resolving power of the electron microscope and many laborious researches on the fine structure of the tumor cell have been reported recently. The fine structure of human hepatoma chosen by biopsy were studied electron microscopically and some interesting findings were obtained.

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Within the past several years, at least six markers of poliovirus have been described which can be determined by tissue culture, physical property and serological method and which tend to discriminate between neurovirulent and attenuated strains. In this communication a report is made on the relationship between the virulence of polioviruses and their antigenicity. The results are summarized as follows: Three known virulent and nine known attenuated strains of poliovirus were used. Rabbits received a single intramuscular injection of 5 ml of virus-adjuvant mixture and two intravenous injections of 5 ml of polioviruses. The rabbits were then examined 15 days after the last injection to determine the production of homo and hetero strainic antibody in theis sera. The injected dose of the virus contained 10⁶ TCD₅₀ per ml. A linear relationship was found to exist between the virulence of poliovirus and its antigenicity in the animal experiment. It is suggested that the immunizing capacity test might serve as a useful test for the virulence of poliovirus. The correlation between in vitro markers of excreted poliovirus and antibody titer of serum in the patient was examined. A linear relationship was found to exist between the virulence of excreted poliovirus and serum antibody titer in the patient.

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