478 L.\WS OF MULTIPLICATION. 



cost no more, or Have an increased cost less than the in- 

 creased gain. In any case, the result is a greater surplus of 

 vital capital ; part of which goes to the aggrandisement 

 of the individual, and part to the formation of new in- 

 dividuals. While the higher tide of nutritive matters, 

 everywhere filling the parent-organism, adds to its power of 

 self- maintenance, it also causes a reproductive overflow larger 

 than before. 



Hence every type that is best adapted to its conditions, 

 which on the average means every higher type, has a rate of 

 multiplication that insures a tendenc}^ to predominate. 

 Survival of the fittest, acting alone, is ever replacing in- 

 ferior species by superior species. But beyond the longer 

 urvival, and therefore greater chance of leaving offspring, 

 which superiority gives, we see here another way in which 

 the spread of the superior is insured. Though the more- 

 evolvad organism is the less fertile absolutely, it is the nior« 

 fertile relatively. 



