VARIATION AND HEREDITY 113 



the genetic relation between successive gen- 

 erations, and an inheritance includes all that 

 an organism is, or has, to start with, in 

 virtue of its hereditary relation. We cannot 

 compare organic inheritance to a patrimony; 

 for the organism and its inheritance are, to 

 begin with, one and the same. Nor do we 

 any longer think of heredity as a power or a 

 principle, as a fate or a force; we study it 

 as a genetic relation, which is sustained by 

 a visible material basis, namely the germ- 

 cells; as a relation of resemblances and 

 differences which can be measured and 

 weighed, or in some way computed. 



The hereditary relation is such that like 

 tends to beget like, while at the same time 

 opportunity is afforded for the individual 

 new departures which we call variations. 

 Both the tendency to persist and the ten- 

 dency to diverge are included in the heredi- 

 taiy relation, so that it is confusing to make 

 an absolute antithesis between heredity and 

 variation. Heredity, seen in its fullest 

 sense, is the larger concept, and includes 

 both inertia and divergence, both con- 

 tinuance and change. Whatever be the 

 terms used, there are two complemental 

 facts: that like tends to beget like, yet that 

 every new creature has in some way an 

 individuality of its own. 



