GENESIS. 297 



race is more likely to be preserved by a rapid asexual pro- 

 pagation of small individuals, which disperse themselves over 

 a wide area of nutrition, than it would be did the indi- 

 vidual growth continue so as to produce large individuals 

 multiplying sexually. And then when autumnal cold and 

 diminishing supply of sap put a check to growth, the recur- 

 rence of gamogenesis, or production of fertilized ova which 

 remain dormant through the winter, is more favourable to 

 the preservation of the race than would be a further con- 

 tinuance of agamogenesis. On the other hand, among 

 the higher animals living on food which, though dispersed, 

 is more or less aggregated into large masses, this alternation 

 of gamic and agamic reproduction ceases to be useful. The 

 development of the germ-product into a single organism of 

 considerable bulk, is in many cases a condition without 

 which these large masses of nutriment could not be appro- 

 priated; and here the formation of many individuals instead 

 of one would be fatal. But we still see the beneficial results 

 of the general law — the postponement of gamogenesis until 

 the rate of growth begins to decline. For so long as the rate 

 of growth continues rapid, there is proof that the organism 

 gets food with facility — that expenditure does not seriously 

 check accumulation; and that the si^e reached is as yet not 

 disadvantageous : or rather, indeed, that it is advantageous. 

 But when the rate of growth is much decreased by the 

 increase of expenditure — when the excess of assimilative 

 power is diminishing so fast as to indicate its approaching 

 disappearance — it becomes needful, for the maintenance of 

 the species, that this excess shall be turned to the production 

 of new individuals; since, did growth continue until there 

 was a complete balancing of assimilation and expenditure, 

 the production of new individuals would be either impossible 

 or fatal to the parent. And it is clear that " natural selec- 

 tion " will continually tend to determine the period at which 

 gamogenesis commences, in such a way as most favours the 

 maintenance of the race. 



