VIII 



THE PREVENTIOX OF THE DEATH OF THE EGG 

 THROUGH THE ACT OF FERTILIZATIOX^ 



I 



The unfertilized egg dies in a comparatively short time, 

 while the act of fertilization gives rise to a series of generations 

 which, theoretically at least, is of infinite duration. The act 

 of fertilization is, therefore, a life-saving act for the egg. The 

 question arises, in which way can the spermatozoon save the 

 life of the egg ? 



If the ovaries of a star-fish are put into sea-water the eggs 

 are shed. They are generally immature, and in this condition 

 they cannot be fertilized, either by spermatozoa or by chemical 

 means. If they remain, however, for some time in sea-water, 

 all or a number of them gradually become mature ; that is to say, 

 their nuclear mass is diminished by the extrusion of the two 

 so-called polar bodies. If immediately after the extrusion of 

 the polar bodies sperm is added, the eggs develop. They can 

 at that period likewise be caused to develop by certain chemical 

 and physical agencies. 



Ten years ago I made the following observations. If the 

 eggs are not caused to develop by sperm or by physico-chemical 

 agencies, they perish very rapidly. At summer temperature 

 they may die in from four to six hours. The death of the egg 

 manifests itself morphologically in a darkening and blackening 

 of the otherwise clear egg. I found that the death of the egg 

 can be prevented by withdrawing the oxygen, or by diiniui>h- 

 ing the rate of oxidations in the egg through the addition of a 

 trace of potassium cyanide. The life-saving action of lack of 



. » Reprinted from the. Harvey Lectures, 1911, by courtesy of Messrs. J. B. 

 Lippincott & Co. 



155 



