ARTIFICIAL PARTHENOGENESIS AND OXIDATIONS 121 
increase is so small that it is not likely to be responsible for the 
corrective action of the hypertonic solution. 
It is more probable that the treatment of the egg with the 
hypertonic solution brings about a permanent change in the 
egg by which it can now undergo the process of membrane 
formation at any time without danger of subsequent disinte- 
gration. This irreversibility of the corrective effect of the 
hypertonic solution would be intelligible on the assumption 
that it is due to the formation of a definite substance which is 
retained by the egg and which is a preventive against the 
disintegration following membrane formation. 
7. We may here discuss parenthetically a hypothesis put 
forward by R. Lillie! concerning the nature of the corrective 
action of the hypertonic solution. Lillie suggests that the 
essential feature in the act of fertilization is an increase in 
the surface permeability of the egg of which the membrane 
formation is the consequence; and that the effect of the ‘‘after- 
treatment with a hypertonic solution is to bring the permeability 
again to normal.” 
We are able to investigate the relative permeability of 
fertilized and unfertilized eggs for bases with the aid of a 
color test, and this color test shows that both unfertilized as 
well as fertilized eggs are permeable for weak and impermeable 
for strong bases.2 As far as acids are concerned, the fact 
found by the writer that weak acids like CO, and the fatty 
acids cause membrane formation in the unfertilized egg shows 
that such an egg must be permeable for these substances. 
McClendon’ has published experiments which he thinks sup- 
port Lillie’s view of an increased ion-permeability of the egg 
after membrane formation, but the writer does not feel 
1R. Lillie, Jour. Morphol., XXII, 695, 1911; Am. Jour. Physiol., XXVII, 
289, 1911. 
20. Warburg, Zeitschr. f. physiol. Chem., LXVI, 305, 1910; N. Harvey, Jour. 
Exper. Zool., X, 507, 1911. 
3 McClendon, Am. Jour. Physiol., X XVII, 240, 1910. 
