CHAPTER IV 



THE HYPOTHETICAL BEARERS OF THE INDIVIDUAL 

 HEREDITARY CHARACTERS 



p. Introduction 



The views on the nature of heredity expressed in the 

 first Section lead us to the conviction that hereditary 

 characters must be units, independent to a higher degree, 

 and combined in nature in the most varied groupings. 



'On the other hand, a critical survey of the theories so 

 far discussed induced us to perceive in all of them a more 

 or less clearly defined kernel, which assumes material 

 bearers for the individual hereditary characters. To shell 

 this kernel was our task, and it had its justification in 

 those views. While the solution of the problem was 

 hitherto achieved with difficulty, this very nucleus is as 

 clear as day in Darwin's pangenesis. 



The assumption of different material bearers for the 

 individual hereditary characters was worked out for the 

 first time by Darwin. The great phenomena of nature 

 which demand this assumption, and of which I could 

 make only a hasty sketch in the first Section, were clearly 

 comprehended and brought together in a masterful man- 

 ner by him. The entire work on "The Variation of Ani- 

 mals and Plants" amounts, so to speak, to establishing the 

 foundation of this fundamental idea, which he has then 

 worked out and tried to harmonize with contradictory 

 experiences. 



It is remarkable that Darwin, with a modesty that puts 

 us to shame, presents this fundamental thought as a cur- 



