364 Death and Dissolution of the Organism 



short and that the entrance of a spermatozoon or the 

 process of artificial parthenogenesis saves the Hfe of 

 the egg. Loeb and Lewis found that the life of the 

 unfertilized sea-urchin egg (which is usually mature 

 when removed from the ovaries) can also be prolonged 

 when its oxidations are suppressed. The decay of the 

 unfertilized egg seems to be due to the fact that those 

 alterations in the cortical layer which underlie the 

 membrane formation and which are responsible for 

 the starting of development gradually take place. 

 In such a condition the egg will die quickly unless 

 deprived of oxygen. This view is supported by the 

 observation of Wasteneys that unfertilized eggs of 

 Arbacia show an increased rate of oxidations when 

 allowed to remain for some time in sea water; we have 

 seen in Chapter V that such an increase also accom- 

 panies artificial membrane formation. 



6. If the limited duration of life of an organism is 

 determined by one or more definite harmful chemical 

 processes, w^e should expect to find a temperature co- 

 efficient for the duration of life or at least be able to 

 show that if all other conditions are the same the dura- 

 tion of life is for a given organism a function of 

 temperature. The writer' investigated the dura- 

 tion of life of fertilized and unfertilized eggs of 

 Strongylocentrotus purpuratus for the upper temper- 

 ature limits. 



' Loeb, J., Arch.f. d. ges. Physiol., 1908, cxxiv., 411. 



