146 PROBLEMS OF FERTILIZATION 



that the material of unfertilized eggs is in a highly oxi- 

 dizable condition. Comminuted material of fertilized 

 eggs consumes no more oxygen than intact fertilized 

 eggs. 



The inference has been drawn from these oxidation 

 studies that the same metabolic activities present before 

 fertilization are accelerated, and that this is the real 

 essence of activation. But the fact that in the 'star- 

 fish there is no measurable increase in oxidation after 

 fertilization, although we have the same phenomenon 

 of initiation of development (activation), sets such a 

 conclusion in a rather doubtful light. It is probable 

 that in the case of the starfish there is an increase in 

 the rate of oxidation during maturation, thus before and 

 independent of fertilization. The connection between 

 fertilization and increase of oxidation may thus be 

 incidental. If we realize that the egg is a highly 

 complex system, and that the rate of oxidation as 

 measured is a gross result without any distinction of 

 kind or location, the obvious alternative stands out 

 that we may be measuring quite different metabolic 

 activities before and after fertilization. If this were 

 the case, it is obvious that the net result in terms of 

 oxygen consumption might not change or might show 

 either a gain or a loss, depending on the nature of the 

 system. There may be a retardation of some processes 

 and an acceleration of others, giving a different net 

 result in the sea urchin and starfish, for instance. 

 The mere determination of gain in oxygen consump- 

 tion, even if it were a universal fact, is not adapted 

 to carry us very far in the problem of fertilization 

 without a more minute analysis. 



