Sutudies on the Intracelluar and Extracellular Potentials of the Lymphatic Heart in Rana Nigromaculata.

1. Monopolar electrograms of posterior lymphatic heart of the frog, in situ,　were observed with the so-called flexibly mounted(3), intracellular microelectrode. The pencil-typed ”wick-electrode'' made of glass tube and cotton wool was also used as an exploring one. 2. The ”overshoot'' of action potential could not be observed. The duration and the amplitude had no constant value. It could not be assures, however, that the intracellular recordings were always successful. 3. A consistent value for the resting potential of the muscle cell was not obtained. It ranged from 20 millivolts to 58, and it is assumed that these varaitions were due not to the failure of the experiments, but to the variable polarized state of the preparation. 4. Monophasic and biphasic potential fluctuations could be seen in the extracellularly recorded electrogram. Comparing them with the simultaneously recorded intracellular potential, it was concluded that the depolarization of the cells could be studied by researching the negatively directed main deflection in the former. It was difficult to analyse there polarization. 5. An assumption that the depolarized state might also be a stable one in the lymphatic heart seemed to be plausible