CHAPTER II. 

 DO DIPLOID SPECIES VARY? 



Armed with the definitions given at the end of the 

 first chapter, we will consider this momentous question. 

 All the more generally accepted Theories of Evolution 

 are based on so called variability. 



We have already seen that the existence of variabili- 

 ty, deduced from the behaviour of individuals belonging 

 to a Linneon, considered to be a unit, is doubtfull. 

 Consequently theories like those of Lamarck and Dar- 

 win, the basis of which is the Linneon considered as a 

 unit, are untenable, unless it can be shown that pure 

 species are able to vary. 



This species undoubtedly are in an uninheritable 

 way. Each species is liable to modification, but such 

 variability is not meant here, the question is whether 

 a species is variable in a transmittable way or not. 



The only sense in which the term variable" can pos- 

 sibly be applied to a homozygous individual, as all indi- 

 viduals belonging to a pure species necessarily are, is 

 the demonstration that a homozygous individual can by 

 itself e. g. without having been crossed, become hetero- 

 zygous, so that an individual, producing until to day 

 only one kind of gametes, would proceed to produce 

 different kinds of gametes to morrow. 



In other words: variability implies the possibility of a 

 monogametic individual becoming polygametic under 



