32 THE EVOLUTION OF LIVING BEINGS. 



As little as the latter fact shows, that silver arose by 

 mutation from the element lead, as little the former 

 shows that the aberrant forms, obtained from self edO. 

 Lamarckiana, arose from the species O. Lamarckiana. 



This is the Lamarckiana-question in a nut-shell. 



DE VRIES has shown that O. Lamarckiana is a hetero- 

 zygote and he has shown nothing else; all the rest is 

 mere hypothesis. 



This very obvious conclusion is corroborated on all 

 sides. 



It is easy to prove the heterozygous condition of O. 

 Lamarckiana by crossing it with its ,,mutants", and by 

 examining the Fx generation, so obtained, according to 

 the Davis-test for specific purity, as to its unifor- 

 mity. 



By so doing we cross according to de Vries' con- 

 ception two pure species (O. Lamarckiana as well as 

 its mutants being considered to be species by him), and 

 consequently should obtain a uniform FI generation. 



Now the result proves by no means this contention. 



In most cases of such crossing we obtain, what de 

 Vries has called segregation in F t , which means nothing 

 else than that the F x generation is not uniform, and 

 from which fact no other conclusion is warranted than 

 that either O. Lamarckiana or the mutant is able to 

 form more than one kind of gametes, consequently is a 

 heterozygote; and as we know that Lamarckiana, as 

 well as the mutants, is able to throw ,,mutants" it is 

 most probable that both are heterozygotes. 



This makes it highly probable that O. Lamarckiana 

 only simulates a species, but in reality is nothing but a 



