Abstract
I found that the electric conductivity of the sea urchin's egg increased about one fourth on fertilization or when made to develop parthenogenetically with sea water containing acetic acid.
Galeotti 1 observed changes in electric conductivity of animal tissues and explained them by the formation and dissociation of ion-proteid compounds. However he observed that the freezing point sometimes did not change appreciably and never changed in proportion to changes in conductivity. Therefore it seems more probable that the changes in conductivity were due to changes in permeability of membranes.
It seems probable, from observations on the volume of the egg, that its osmotic pressure does not appreciably change, even momentarily, on fertilization. For this and other reasons 2 I conclude that the increased electric conductivity is due to increased permeability of the plasma membrane.
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