ii.] PROCESSES IN HEREDITY. 9 



they did. They form what is well expressed by the 

 word " traits," traits of feature and character — that is to 

 say, continuous features and not isolated points. 



We appear, then, to be severally built up out of a 

 host of minute particles of whose nature we know 

 nothing, any one of which may be derived from any 

 one progenitor, but which are usually transmitted in 

 aggregates, considerable groups being derived from 

 the same progenitor. It would seem that while the 

 embryo is developing itself, the particles more or less 

 qualified for each new post wait as it were in com- 

 petition, to obtain it. Also that the particle that 

 succeeds, must owe its success partly- to accident of 

 position and partly to being better qualified than any 

 equally well placed competitor to gain a lodgment. 

 Thus the step by step development of the embryo 

 cannot fail to be influenced by an incalculable number 

 . of small and mostly unknown circumstances. 



Family Likeness and Individual Variation. — Natural 

 peculiarities are apparently due to two broadly different 

 causes, the one is Family Likeness and the other is In- 

 dividual Variation. They seem to be fundamentally 

 opposed, and to require independent discussion, but this 

 is not the case altogether, nor indeed in the greater part. 

 It will soon be understood how the conditions that pro- 

 duce a general resemblance between the offspring and 

 their parents, must at the same time give rise to a con- 

 siderable amount of individual differences. Therefore I 

 need not discuss Family Likeness and Individual Varia- 



