The Relations of Temperature to the Potassium Effect and the Bioelectric Potential of Valonia

The effect of temperature upon the bioelectric potential across the protoplasm of impaled Valonia cells is described. Over the ordinary tolerated range, the P.D. is lowest around 25 degrees C., rising both toward 15 degrees and 35 degrees . The time curves are characteristic also. The magnitude of the temperature effect can be controlled by changing the KCl content of the sea water (normally 0.012 M): the magnitude is greatly reduced at 0.006 M KCl, enhanced at 0.024 M, and greatly exaggerated at 0.1 M KCl. Conversely, temperature controls the magnitude of the potassium effect, which is smallest at 25 degrees , with a cusped time course. It is increased, with a smoothly rising course, at 15 degrees , and considerably enhanced, with only a small cusp, at 35 degrees . A temporary "alteration" of the protoplasmic surface by the potassium is suggested to account for the time courses. This alteration does not occur at 15 degrees ; the protoplasm recovers only slowly and incompletely at 25 degrees , but rapidly at 35 degrees , in such fashion as to make the P.D. more negative than at 15 degrees . This would account for the temperature effects observed in ordinary sea water.