THE EFFECT OF ALKALIES ON THE OXYGEN CONSUMPTION AND SUSCEPTIBILITY OF PLANARIA DOROTOCEPHALA

Abstract

1. The general result of exposing Planaria dorotocephala to water whose alkalinity is increased from pH 7.6 or 7.8 to 8.0 to 9.2 by addition of NaOH or to 8.0 to 8.8 by addition of NH₄OH is an increase in the rate of oxygen consumption, whether the exposure is for long or short periods. 2. The increase lasts as long as the planarians remain in the alkaline water (longest experiment, two weeks). A return to the normal or to a lower rate (probably result of starvation) occurs at once when the animals are returned to water of the original pH. 3. The resistance of planarians to lethal concentrations of alkali is not altered by long exposure (ten days) to non-injurious concentrations of alkali. 4. The susceptibility of planarians to toxic chemical solutions, to lack of oxygen, and to ultraviolet radiation is greater when they are exposed to these conditions at pH 9.0 than when exposed at ordinary alkalinity of normal water (pH 7.8 to 8.0).