BIOELECTRIC POTENTIALS IN HALICYSTIS VII. rIME EFFECTS OF LOW OXXGEN

Previous work I has shown that the existing or experimentally altered gradients of inorganic ions or other substances between the environment and the vacuolar sap of impaled ceils of ttalicystis have little influence upon the large and steady potential difference measurable across the protoplasm. The r61e of the latter, with its inherent gradients and asymmetries was therefore emphasized in the earlier title of this series: "protoplasmic potentials." Although it seems desirable to alter this to the more general term now used, it is particularly the "protoplasmic" aspects which will be considered in the next several papers. Since the cell's E. M. ~. can drive an appreciable current of 5 to 10 microamperes through a completed circuit for many days, a source of energy, eventually metabolic, is indicated. Agents affecting metabolism, such as oxygen tension, temperature, light, inhibitors, and stimulants, will therefore be discussed in the next few papers, with a view to indicating how metabolism may produce or alter the bioelectric potential. The present paper is restricted to the effects of altered oxygen ten-