122 AKTIFICIAL PARTHENOGENESIS AND FERTILIZATION 



that McClendon's interpretation of the experiment is the only 

 one admissible. 



McClendon investigated the electrical conductivity of un- 

 fertilized and fertilized eggs and found that the conductivity 

 of the egg is increased by fertilization. He concludes that 

 this proves an increased permeability of the egg for ions, 

 but the same result would be produced if in consequence of 

 fertilization or membrane formation the degree of electrolytic 

 dissociation in the surface film of the egg should be increased. 

 The egg or its surface film must be considered as a non-aqueous 

 phase and the conductivity in this phase depends among others 

 upon the degree of electrolytic dissociation of the electrolytes 

 dissolved in it. It is quite conceivable that so considerable a 

 change hi the cortical layer as that taking place in membrane 

 formation might influence the degree of solubility or of electro- 

 lytic dissociation in the surface film of the egg. 



McClendon made also the interesting observation that "if 

 fertilized and unfertilized eggs of Arbacia are placed in an iso- 

 tonic sugar solution containing little sea-water, through which 

 a current of gradually increasing density is passed, the unferti- 

 lized eggs begin to disintegrate, at their anode ends, sooner than 

 the fertilized eggs." He interprets this as "indicating that the 

 fertilized eggs are more permeable to anions, which therefore 

 accumulate in them to a less extent, or the fertilized eggs are 

 more permeable to electrolytes, which therefore have passed 

 out into the sugar solution to a greater extent, and therefore 

 the current passes through them less, than in the case of the 

 unfertilized eggs." I believe that the phenomenon described 

 by McClendon is not sufficiently understood to lend itself to 

 conclusions concerning the permeability of the egg. But these 

 questions do not concern us here so much as the action of the 

 hypertonic solution. 



The idea that the treatment of the egg with the hypertonic 

 solution serves the purpose of restoring the increased permeability 



