XXX 
PRESERVATION OF THE LIFE OF THE EGG BY THE ACT 
OF FERTILIZATION 
1. The unfertilized egg dies in a comparatively short time, 
while the act of fertilization saves the life of the egg and allows 
it to give rise, theoretically at least, to an unlimited series of 
generations. The question arises: How does the spermatozoon 
save the life of the egg? It is not necessary to emphasize the 
physiological importance of this feature of the process of ferti- 
lization. 
The rapidity with which the unfertilized eggs die differs 
according to the species. The unfertilized egg of the starfish 
(Asterias) dies at summer temperature in a few hours, that of 
Polynoe in less than a day, while that of the sea-urchin (A rbacia) 
may live for a week or longer. In all cases the life of the 
unfertilized egg can be prolonged if its oxidations are suppressed; 
and the rapidity with which they die seems to depend upon the 
relative velocity of oxidations in the unfertilized egg. 
As already mentioned, the eggs of the starfish are mostly 
unripe when laid, and they only begin to ripen in sea-water. 
The different eggs, however, do not all ripen at the same rate. 
Now I found that if mature eggs were not at once or soon 
fertilized or caused to develop by chemical means, they quickly 
disintegrate, i.e., in the course of a few hours. 
The cytoplasm of the living eggs of Asterias is homogeneous 
and of a light yellowish color. This appearance the eggs also 
retain after maturation, as long as they are alive; nor do they 
lose it if development is initiated by the entry of a spermatozoon 
or by the methods of artificial parthenogenesis. 
If, however, the ripe eggs remain unfertilized or are not 
caused to develop, they die in the course of from four to twelve 
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