122 ArtiricIAL 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 in 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 
