NatTurRAL 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 
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