Electrical Control of Organic Polarity in the Egg of Fucus

Polarity of the egg of Fucus can definitely be determined by applying a difference of electrical potential to the egg. Apparently this is the first egg, among either animals or plants, the polarity of which has been controlled by means of an electric current. The response of the Fucus egg to the electric current in total darkness is similar to its response to light. 2. A method is given by which it is possible to measure the P.D. across a single egg which is placed in an electric current flowing in a stream of sea water of constant cross-section. 3. The magnitude of the electrical potential applied to opposite sides of an egg, which is just able to cause orientation (threshold P.D.) of the axis of symmetry of the protoplasm of the Fucus egg, is 0.025±0.002 volts. 4. This threshold P.D. is definite and does not appear to involve any marked inhibitory effect (delay) upon growth. A P.D. of 0.036 volts applied to the egg does show an inhibitory effect (delay) upon cleavage. 5. The establishment of an electrochemical polarity of some sort may possibly be a fundamentally associated condition for the development of morphological polarity, because the physiological mechanism in the Fucus egg which determines morphological polarity can be controlled and directed by the application to the egg of a difference of electrical potential of external origin.