190 ARTIFICIAL PARTHENOGENESIS AND FERTILIZATION 



larger ones. In that case, less of the light passing through it 

 will be reflected, and the eggs appear clear. A glance at Fig. 51 

 shows that as a matter of fact the cytolyzed egg consists of 

 large drops. It appears possible that the outflow of the clear 

 drops in the cytolysis of the moderately unpigmented egg of 

 S. purpuratus may correspond to the outflow of haemoglobin 

 from the red blood corpuscles. It is to be noted that in this 

 case it is unnecessary to assume a bursting of the surface layer 

 of the red blood corpuscle. 



But from the point of view of our work, it is not necessary 

 to venture upon a decision with regard to the lipoid controversy 

 and cytolysis. We can observe directly that cytolytic sub- 

 stances cause the chorion that surrounds the eggs to swell and 

 then gradually to dissolve completely. It is necessary only for 

 us to make use of this observation in order to understand mem- 

 brane formation also. If we assume that in the cytoplasm of 

 the egg itself there is present near the surface a substance that 

 is identical with or closely allied to one of those in the chorion, 

 we can understand that this must be made to swell and liquefy 

 before the egg can develop. 



The swelling and solution of such a substance in the interior 

 of the egg causes cytolysis, and hence it comes about that all 

 cytolytic substances or reagents also produce an effect that 

 leads to membrane formation, and hence to artificial partheno- 

 genesis. 



