Transmission of Grandparental Characters 239 



larly to be sacrificed every time.^ Therefore fertiliza- 

 tion may result in offspring with pronuclei from the 

 grandfather or grandmother only, or from both. This 

 circumstance may not be without significance in consid- 

 ering the resemblance between grandparents and grand- 

 children among men. 



But it is not by any means decisive; daily experience 

 teaches that not only in a part of the progeny, but doubt- 

 less in all the offspring, there may be an admixture of the 

 characters of the grand-parents also. This indicates that 

 the separation of the pronuclei is not of as simple a nature 

 as the microscopic pictures might lead one to believe. 

 Another process, which, until now, has defied detection, 

 must take place, probably in the smallest, but to us invisi- 

 ble granules of the nuclear threads. That this is the 

 case we learn especially from the processes in hybrids 

 and their propagation. Here, splittings and new combin- 

 ations of the characteristics of the grand-parents occur 

 in apparently incalculable numbers, and here it is dis- 

 tinctly seen that the pronuclei do not separate without 

 a lasting reciprocal influence. 



We shall first try to get a conception of this influ- 

 ence, for the facts concerning hybridization are rather 

 involved; they can be most clearly explained by means 

 of such a hypothetical conception. We shall accordingly 

 assume a mutual influence as an established fact, and in- 

 quire how this can take place. 



First of all it is clear that it must be finished before 

 the separation of the pronuclei. Once they are apart all 

 intimate relation between them ceases. They go their 

 separate ways, each living for itself. Only in the double 



^Xhe reference is to the resorption of the sister-cells (when such 

 occur) of the embryo-sac mother-cell. Tr. 



