CHAPTER XIX. 



CONCLUSIONS FROM THE BEHAVIOUR OF DIPLOID 

 ORGANISMS. 



New forms arise as the result of a cross; they can 

 gradually become specifically pure by segregation if 

 self-fertilization prevails. 



Once pure, they perpetuate themselves by heredity 

 and constitute a species. 



Several of such species are united by systematists to 

 Linneons. A Linneon of this kind e. g. a Linneon consist- 

 ing of habitual self fertilizers, gradually looses species by 

 extermination through the struggle for life, which pro- 

 cess may result in the survival of one species within such 

 a Linneon only, which species is then called selected. 



Selection therefore spells: extermination. 



Such a Linneon, reduced to one species, becomes sy- 

 nonymous with species and can withstand changes of 

 conditions only, by non-transmittable plasticity, which 

 is frequently called adaptability. 



The usual idea that a species can survive by adapting 

 itself to changed conditions by transmittable variabili- 

 ty, is not only wrong, because such transmittable varia- 

 bility does not exist, but also because the result of such 

 a process would be the creation of new species and 

 consequently not assure the survival of the old one, 

 but its replacement by others. 



