NATURAL DEATH AND FERTILIZATION 741 



mining factor in the chemical forces set in motion within the 

 egg through fertilization consists in this that the synthetical 

 processes in the egg are accelerated. If these processes are 

 not inaugurated or accelerated the egg dies. The wasting 

 of the body in old age also indicates a decrease in syntheti- 

 cal processes. Whether the second critical period occurring 

 in old age is similar to the critical period of the egg cannot 

 yet be determined. Yet it is not impossible -that the ques- 

 tion of the prolongation of life at this period should pass 

 over into the question of the possibility of accelerating 

 synthetical processes. 



We, therefore, come to the conclusion that fertilization 

 accelerates a series of chemical changes (syntheses?) in the 

 eggs which do not occur sufficiently rapidly without spermatic, 

 chemical, or osmotic fertilization in the eggs of the majority 

 of animals. But why does the mature egg die when these 

 processes are not accelerated, and why does it remain alive 

 before it maturates ? The egg must often exist for years in 

 the immature condition in the ovary. In answer I can 

 only suggest that the processes underlying maturation are 

 at least in some form of a destructive nature (one might 

 think of autolytic processes) which the egg cannot withstand 

 for an indefinite length of time without dying. In many 

 eggs the velocity of these destructive (autolytic?) processes 

 may be greater than in others and this may determine the 

 differences in the velocity with which the mature, unfer- 

 tilized egg dies. It is in harmony with this view that 

 when maturation is prevented, or the mature egg is put un- 

 der conditions which inhibit the process of maturation or the 

 chemical processes underlying it, the life of the egg is 

 lengthened. Lack of oxygen or the addition of an acid 

 works in this way in the case of starfish eggs ; a slight addi- 

 tion of potassium cyanide, in the case of starfish and sea- 

 urchin eggs. But since all of these substances injure the 



