GERMINAL SELECTION 473 



generalisations — Galtonian and Mendelian — we are accustomed, 

 in predicting the issue of crossings, to say that the offspring will 

 exhibit a blended, or exclusive, or particulate expression of the 

 parental characters. How often, however, must we not frankly 

 admit, the individual result seems anomalous ! Now, is not this 

 result just what we should expect if germinal struggle is a reality ? 

 2. No phenomenon of inheritance is more familiar than that 

 of preponderant and exclusive inheritance, where, in regard to the 

 expression or development of a given character, the offspring follows 

 one parent preponderantly or exclusively, instead of being merely 

 a " blend." If we suppose that ovum and spermatozoon have each 

 a complete organisation of hereditary qualities (as we seem bound 

 to suppose), and that the fertilised ovum has determinants repre- 

 senting the character in question from both parents and from the 

 ancestors of both parents, may we not consistently interpret the 

 hereditary re-expression of only one set, by supposing that there 

 is a struggle for expression between the various sets — a struggle 

 in which the most vigorous have for the time the mastery ? 



3. A frequent phenomenon of inheritance is a change in the 

 direction of preponderance in the successive children of a large 

 family. Suppose a virile middle-aged father and a much younger 

 mother : the older children may be markedly paternal in the 

 expression of their inheritance, the younger children as markedly 

 of the maternal type. Introduce the conception of germinal 

 struggle ; suppose it to occur not only in the germ-cell lineage 

 within the gonads, but in the fertilisation and afterwards ; recall 

 the fact that the ova tend to be more stable than the spermatozoa, 

 being formed and to some extent fixed in very early days, whereas 

 the spermatozoa continue to appear in crop after crop. At first 

 we picture a victory on the part of the determinants of the relatively 

 prepotent father ; but gradually, in his post-mature spermatogenesis, 

 there is a weakening of paternal determinants such that, in fertilisa- 

 tion, those from the mother have now a better chance of asserting 

 themselves. Naturally enough, the Benjamin is after the mother's 

 image and after the father's own heart. 



4. A very young pigeon of hooded or frilled breed is mated with 

 an old one : the first young are smooth-headed and smooth-breasted, 

 but those of later broods have the specialised characteristics of the 

 parents. May this not mean that in the too-young egg-cells the more 

 recent determinants as to head- and breast-feathers — though in the 



