92 ARTIFICIAL PARTHENOGENESIS AND FERTILIZATION 



It is very characteristic that the eggs usually disintegrate 

 not while they are in the hypertonic solution but after they 

 have been put back into the normal sea-water. This agrees with 

 the observation we made on the disintegration of the egg after 

 membrane formation, namely, that this disintegration begins 

 at the time of the first cell division. The hypertonic solution 

 does not permit cell division, while the cell division begins in an 

 irregular way after the eggs are transferred to normal sea-water. 

 Such eggs disintegrate into little droplets. 



The unfertilized eggs do not suffer as quickly in the hyper- 

 tonic solution as the fertilized eggs. In the unfertilized egg 

 the hypertonic solution must first induce some parthenogenetic 

 changes before it can produce its destructive action. 



5. We must in this connection consider an idea emphasized 

 by various authors that the fertilized egg is more permeable 

 than the unfertilized. On this assumption we might understand 

 why the fertilized egg is more easily destroyed in abnormal salt 

 solutions than the unfertilized egg. Leaving aside temporarily 

 the fact that the fertilized egg is protected for some time against 

 the action of the same agencies if its development is prevented 

 by lack of oxygen, this idea meets with other difficulties. If 

 this view were correct, the egg should be permeable for such 

 substances as NaOH, and the fertilized egg much more so than 

 the unfertilized egg. The observations of Warburg and Harvey 

 to be mentioned later have definitely shown that this is not the 

 case. But how are we then to explain such phenomena as the 

 following? The egg of Arbacia possesses a red pigment. If 

 fertilized and unfertilized eggs are put into an alkaline solution, 

 e.g., 50c.c. m/2 NaCl + 1 c.c. m/2 BaCl 2 +0.2 c.c. N/10 

 NaOH, the fertilized eggs lose their pigment almost instantly 

 while the unfertilized eggs keep it for a long time. 1 The explana- 

 tion lies probably in the fact that the alkaline solution comes 

 into direct contact with the cytoplasm of the fertilized egg, 



Biochem. Zeitschr., XXIX, 93, 1910. 



