The essay on "Fertilization and Hybridization" was read in 

 Haarlem in the Dutch language, and appears here in an enlarged 

 form. My conception of the life-processes in the nuclei is chiefly 

 based on the renowned investigations of van Beneden and of Boveri, 

 as well as the most recent researches by Conklin {Contr. Zool. Lab. 

 Pennsylvania, XH, 192), Sutton {Biol Bull IV, Dec, 1902), Eisen, 

 {Jour. Morphol XVH, 1), Errera {Revue Scientif. Feb., 1903), and 

 of many others. For the literature I refer to E. B, Wilson, The 

 Cell in Development and Inheritance, and V. Hacker, Praxis und 

 Theorie der Zellen-und Befruchtungslehre. 



My presentation of the processes of fertilization and hybridiza- 

 tion is an outcome of the experiments which I have described in the 

 second volume of my Mutationstheorie (Leipsic, Veit & Co., 1901- 

 1903. English translation by Open Court Publishing Co., 1909-1910.) 



H de V. 



