THE PROBLEM OF ACTIVATION 267 



viz., specificity, irreversibility, and activation, for these 

 are inseparable. The penetration of the spermatozoon 

 and the union of the germ nuclei are results of these 

 primary factors of the fertilization reaction, and they 

 constitute, therefore, secondary problems, even though 

 from a teleological point of view they represent the 

 essence of the entire process. 



It is hoped that the writer's fertilizin hypothesis 

 presented in various places in this book at least supple- 

 ments other theories of activation and points the way 

 to a more inclusive theory that shall comprise all the 

 main aspects of fertilization. 



REFERENCES 



ALLYN, HARRIET M. 



1912. "The Initiation of Development in Chaetopterus" 

 Biol. Bull., XXIV, 21-72. 



BATAILLON, E. 



1909. "L'impregnation heterogene sans amphimixie nucle- 

 aire chez les amphibiens et les echinodermes," Arch. 

 fur Entwickelungsmech., T. 38. 



1910^7. "L'embryogenese complete provoquee chez les am- 

 phibiens par piqure de 1'ccuf vierge, larves parthe- 

 nogenetiques de Rana fusca," Comptes rendus de 

 VAcad. de. Sci.^T. 150. 



1910^. Le probleme de la fecondation circonscrit par 

 1'impregnation sans amphimixie et la parthenogenese 

 traumatique," Arch, de zool. exp. et gen., Ser. 5, T. 6, 

 pp. 101-35. 



19110. "Les deux facteurs de la parthenogenese trauma- 

 tiques chez les amphibiens," Comptes rendus de 

 VAcad. de Sci., T. 152. 



191 ib. "L'embryogenese provoquee chez Tceuf vierge d'am- 

 phibiens par innoculation de sang ou de spermes de 

 mafnmiferes," etc., ibid. 



