172 LAWS OF MULTIPLICATION. 



to special facts, we have found that this inverse variation is 

 clearly traceable throughout both the animal and vegetal 

 kingdoms. We may therefore set it dovrn as a law, that 

 everv higrher de^rree of oro^anic evolution, has for its con- 

 comitant a lower degree of that peculiar organic dissolution 

 which is seen in the production of new organisms. 



§ 363. Something remains to be said in reply to the in- 

 quiry — how is the ratio between Individuation and Genesis 

 established in each case ? This inquiry has been but partially 

 answered in the course of the foregoing argument. 



All specialities of the reproductive process are due to the 

 natural selection of favourable variations. Whether a creature 

 lays a few large eggs or many small ones equal in weight to 

 the few large, is not determined by any phj-siological neces- 

 sity : here the onh^ assignable cause is the survival of varieties 

 in which the matter devoted to reproduction, happens to be 

 divided into portions of such size and number as most to 

 favour multiplication. Whether in any case there are 

 frequent small broods or larger broods at longer intervals, 

 depends wholly on the constitutional peculiarity that has 

 arisen from the dying out of families in which the sizes and 

 intervals of the broods were least suited to the conditions of 

 life. Whether a species of animal produces many offspring 

 of which it takes no care or a few of which it takes much 

 care — that is, whether its reproductive surplus is laid out 

 wholly in germs or partly in germs and partly in labour on 

 their behalf — must have been decided by that moulding of 

 constitution to conditions, slowly effected through the more 

 frequent preservation of descendants from those whose re- 

 productive habits were best adapted to the circum- 

 stances of the species. Given a certain surplus available 

 for race-preservation, and it is clear that by indirect 

 equilibration only, can there be established the more or 

 less peculiar distribution of this surplus which we see in 

 each case. Obviouslv, too, survival of the fittest 



