1/8 DYNAMICS OF LIVING MATTER 



lead to the development of the egg unless the egg has been submitted 

 for twenty minutes to the hypertonic sea water. It is therefore obvious 

 that the process of astrosphere formation or similar alterations cannot 

 be the direct efifect of the act of fertilization and, moreover, it cannot be 

 the essential feature of it. I am inclined to believe that the direct and 

 essential efifect of the spermatozoon and the methods of artificial par- 

 thenogenesis is the starting of a definite chemical process, and that the 

 formation of astrospheres is only a secondary effect of this. 



It is in harmony with this idea that the process of segmentation in 

 the case of artificial parthenogenesis is entirely regular, and does not 

 differ from that of fertihzed eggs, provided that the right concentration 

 and time of exposure are selected. 



I have not entered into a discussion of the cytological changes which 

 are noticeable in an egg in which artificial parthenogenesis has been 

 produced, and refer the reader to a masterly paper* by E. B. Wilson on 

 this subject. 



* E. B. Wilson, Archiv fur Entwickelungsmechanik, Vol. 12, p. 552, igoi. 



