GENEOLOGICAL. 407 



incompleteness in the inheritance. Indeed, the fact 

 that resemblance so often reappears in the third 

 generation, makes it probable that the incompleteness 

 is not in the inheritance but simply in its expression. 

 The characters which seem to be absent, to " skip a 

 generation," as we say, are probably part of the in- 

 heritance, as usual. But they remain latent, neutral- 

 ised, silenced (we can only use metaphors) by other 

 characters, or else unexpressed because of the ab- 

 sence of the appropriate stimulus. 



The three most frequent modes of inheritance are, 

 for convenience, called blended, exclusive, and par- 

 ti culaie. 



(a) In blended inheritance, the characters of the 

 two parents, e.g., in regard to a particular structure, 

 such as the colour of the hair, are intimately com- 

 bined in the offspring. This is particularly well 

 seen in some hybrids, where the offspring seems like 

 the mean of the two parents ; it is probably the most 

 frequent mode of inheritance. 



(6) In exclusive inheritance, the expression of 

 maternal or of paternal characters in relation to a 

 given structure, such as eye-colour, is suppressed. 

 Sometimes the unilateral resemblance is very pro- 

 nounced, and we say that the boy is " the very image 

 of his father," or the daughter " her mother over 

 again " ; though even more frequently the resem- 

 blance seems " crossed," the son taking after the 

 mother, and the daughter after the father. 



(c) It seems convenient to have a third category 

 for cases where there is neither blending nor exclu- 

 siveness, but where in the expression of a given 

 character, part is wholly paternal and part wholly 

 maternal. This is called particulate inheritance. 

 Thus, an English sheep-dog may have a paternal eye 



2 A 



