Abstract
In a series of previous papers it was shown that the process underlying the formation of the fertilization membrane is the essential act in the causation of development. It was further shown that this process is essentially a cytolysis or liquefaction of the superficial (cortical) layer of the cytoplasm of the egg. The question arose, how can this cytolysis or liquefaction cause the egg to develop. It seemed natural to think first of the possibility that the superficial cytolysis rendered the egg more permeable for substances required for its development.
The possibility that fertilization might increase the permeability of the egg had been considered by me in 1906 (Biochem. Zeit., 1906, ii, 87). I had found that a pure solution of sodium chloride is practically harmless for the unfertilized, but very toxic for the fertilized egg. Since lack of oxygen is likewise harmless for the unfertilized and very harmful for the fertilized egg, I was inclined to ascribe the difference in the toxic effect of sodium chloride to a difference in the velocity of chemical reactions and not to a difference in the permeability of the fertilized and unfertilized egg. I have recently resumed the investigation of this question with regard to the action of salts, alkalis and acids.
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