THE EVOLUTION OF LIVING BEINGS. 75 



„It thus appears that if the number of separable 

 „hereditable characters is not very great (say not 

 „ above ioo), while the organism has been self fer- 

 tilized for many generations, it is to be expected 

 „that practically all of the organisms will be homo- 

 „zygotic with respect to all their characters, they 

 „will be „pure homozygotes" 

 In other words this calculation leads to a result re- 

 sembling that of a Linneon, like Triticum vulgare, con- 

 sisting of a large number of different pure lines. 



Now let us see what the calculation of what hap- 

 pens in an intercrossing population of segregates from 

 a cross, will teach us. 



Calculation of whatis likely to happen, if 

 free intercrossing follows an initial 

 crossbetween organisms, diffe- 

 ring in one or more respects. 



This has been calculated repeatedly, always with the 

 same result f. i. by Baur 2d edition p. 123 — 129. The 

 simplest calculation I am acquainted with is by Reimers 

 in a forthcoming article on „Die Bedeutung des Mende- 

 lismus fur die landwirtschaftliche Tierzucht" which 

 will soon be published by Martinus Nijhoff in the Ha- 

 gue. He argues about in the following way: 

 1. The parents differ in one factor only. 



If we call this factor A and its absence a, all ¥ x 

 individuals must be Aa. In F 2 we will find the same 

 proportions as after self fertilisation, because it is 

 of course indifferent, whether the eggcell A or a is 

 fertilised by Pollen A or a, derived from the same, 



