X 



FURTHER EXAMPLES OF THE PROLONGATION OF THE 

 LIFE OF THE EGG BY LACK OF OXYGEN 



1. It is rather curious that lack of oxygen, or probably the 

 suppression of cell division, should be able to delay the disinte- 

 gration with which the egg of the sea-urchin is threatened after 

 artificial membrane formation. We found an explanation for 

 this phenomenon in the fact that the process of nuclear or cell 

 division is critical for the egg in danger of disintegration. If 

 one suppresses this process the disintegration is markedly 

 retarded. The cell division can be suppressed or retarded by 

 the suppression of oxidations as well as by narcotics. 1 We also 

 called attention to the fact that if we allow normally fertilized 

 eggs to segment in abnormal solutions, the process of cell divi- 

 sion is also accompanied by processes of disintegration (droplet 

 formation) comparable to those which are characteristic for the 

 egg after artificial membrane formation. We should therefore 

 have a right to expect that if we put fertilized eggs into abnormal 

 solutions, their lives will be prolonged if we inhibit cell division 

 either by lack of oxygen or by KCN or by other means which 

 inhibit cell division, e.g., narcotics. We should also logically 

 be led to suppose that unfertilized eggs will live longer in such 

 abnormal solutions than fertilized eggs, simply for the reason 

 that they are not threatened with nuclear or cell division. 



The writer has made a series of observations which show 

 that quite generally unfertilized eggs suffer less in abnormal 

 solutions than fertilized eggs; and that fertilized eggs suffer 

 less rapidly if their oxidations are suppressed. 



1 The narcotics suppress or retard the process of cell division and development 

 without diminishing the rate of oxidation in the egg noticeably. Loeb and Waste- 

 neys, Jour. Biol. Chem., XIV, 518, 1913. 



85 



