THE EVOLUTION OF LIVING BEINGS. 95 



cing themselves apagomously as in the case of Tara- 

 xum officinale, it may consist chiefly of pure domi- 

 nants and hybrids, resembling these, with a sUght ad- 

 mixture of pure species (the recessives) as in the case of 

 the wild rabbits or of the brown-flowered Cheiranthus 

 Cheiri, or it may consist of almost nothing but hy- 

 brids of different constitutions, as it does f . i. in the 

 case of Symph5^um officinale and of human beings. 

 That, even in such cases as these last ones, we keep up 

 the conception of a Linneon, is caused by the fact that 

 we are impregnated, from infancy almost, with the con- 

 viction that some characters are essential for a Linneon 

 while others are not, so that we refuse to cut up a Lin- 

 neon into smaller groups, as long as these „essential" 

 characters e. g. those common to all the different tj^es 

 within the Linneon, are not brought into play, which 

 of course they never can, as we ourselves did Umit the 

 Linneon by the criterium of the very presence of these 

 characters in all its individuals. 



