Translators Preface ix 



of the egg he postulates a fusion of maternal with pater- 

 nal pangens.^ Thus, in the gametopliA^tic generation, the 

 pangens must be considered as univalent (haploid), in 

 the sporophytic as bivalent {diploid). This would lead 

 us to look for larger nuclei in the cells of the sporophyte 

 than in those of the gametophyte. This hypothesis was 

 verified in a number of plants, widely separated system- 

 atically. In Taxns haccata, for example, the nuclei of 

 the prothallus were noticeably smaller than those of the 

 sporophyte : and in nuclei with equally marked granula- 

 tion, Strasburger counted fifty granules in an optical sec- 

 tion of the nuclei of the nucellus, and only one-half that 

 number in the nuclei of the adjacent prothallus. 



But I cite this paper of Strasburger's chiefly to show 

 how the hypothesis of intracellular pangenesis, in other 

 hands that its author's, may assist in forming some com- 

 prehensible picture of the mechanism of matter in the 

 living state. The idea and the term pangen are also 

 adopted by Pfeffer in his Physiology of Plants.^ 



At the suggestion of Professor de Vries, a transla- 

 tion of his Haarlem Vortrag on ''Befrnchtiing iind Bas- 

 tardicning" is included in this volume, for the purpose of 

 showing the bearing of more recent research on the hy- 

 pothesis of intracellular pangenesis, and of thus bringing 

 the problem more nearly down to date. The translation 

 of this Vortrag also appeared in ''The Monist," for No- 

 vember, 1909. 



It is a pleasure to record my profound gratitude to 

 Professor de Vries for his careful reading and annota- 

 tion of the manuscript of the translation, and for his inter- 

 est and encouragement throughout the undertaking. 



^loc. cit. p. 61. 



^Pfeffer W. The Physiology of Plants. Eng. Trans, by Alfred 

 J. Ewart. 1: 49. Oxford, 1900.' 



