12 COSMIC FHILOSOPHY. [pt. ii. 



continue at this rate for three or four years, the ocean would 

 not afford room for the species. Yet we liave no reason to 

 suppose that the race of codfishes is actually increasing in 

 numbers to any notable extent. With the codfish, as with 

 animal species in general, the numbers during many succes- 

 sive generations oscillate about a point which is fixed, or 

 moves but slowly forward or backward. Instead of a 

 geometrical increase with a ratio of six millions, there is 

 practically no marked increase at all. N'ow this implies that 

 out of the six million embryo codfish a sufficient number 

 will survive to replace their two parents, and to replace a 

 certain small proportion of those contemporary codfishes who 

 leave no progeny. Perhaps a dozen may suffice for this, 

 perhaps a hundred. The rest of the six million must die. 

 We may thus understand what is meant by the " struggle 

 for existence." Battles far more deadly than those of 

 Gettysburg or Gravelotte have been incessantly waged on 

 every square mile of the earth's life-bearing surface, since 

 life first began. It is only thus that the enormous increase 

 of each species has been kept within bounds. Of tlie many 

 offspring produced by each plant and animal, save in the case 

 of those highest in the scale, but few attain maturity and 

 leave offspring behind tliem. The most perish for want of 

 sustenance, or are slain to furnish food for other organisms. 

 There is thus an unceasing struggle for life — a competition 

 for the means of subsistence — going on among all plants and 

 animals. In this struggle by far the greater number succumb 

 without leaving offspring, but a few favoured ones in each 

 generation survive and propagate to their offspring the 

 qualities by virtue of which they have survived. 



Thus we see what is meant by " Natural Selection." The 

 organisms which survive and propagate their kind are those 

 which are best adapted to the conditions in which they live* 

 so that we may, by a legitimate use of metaphor, perponify 

 Nature as a mighty breeder, selecting from each general ion 



