Translator's Preface ix 



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

 nal pangens. 8 Thus, in the gametophytic generation, the 

 pangens must be considered as univalent (haploid), in 

 the sporophytic as bivalent (dlploid). 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 Taxus baccata, 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. 9 



At the suggestion of Professor de Vries, a transla- 

 tion of his Haarlem Vortrag on "Befruchtung und Bas- 

 tardierung" 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. 



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

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



