262 Darwin, and after J^anvin. 



year, if these in successive years were all allowed 

 to reproduce their kind, in twenty years there would 

 be 11,000,000 plants from a single ancestor. Yet we 

 know that nearly all animals and plants produce 

 many more young at a time than in either of these 

 two supposed cases. Indeed, as individuals of many 

 kinds of plants, and not a few kinds of animals, pro- 

 duce every year several thousand young, we may make 

 a rough estimate and say, that over organic nature as a 

 whole probably not one in a thousand young are al- 

 lowed to survive to the age of reproduction. How 

 tremendous, therefore, must be the struggle for exis- 

 tence I It is thought a terrible thing in battle when 

 one half the whole number of combatants perish. But 

 what are we to think of a baltle for life where only 

 one in a thousand survives ? 



This, then, is the first fact. The second is the fact 

 so long ago recognised, that the battle is to the strong, 

 the race to the swift. The thousandth individual 

 which does survive in the battle for existence which 

 does win the race for life is, without question, one 

 of the individuals best fitted to do so ; that is to say, 

 best fitted to the conditions of its existence considered 

 as a whole. Nature is, therefore, always picking out, 

 or selecting, such individuals to live and to breed. 



The third fact is, that the individuals so selected 

 transmit their favourable qualities to their offspring 

 by heredity. There is no doubt about this fact, so 

 far as we are concerned with it. For although, as I 

 have already hinted, considerable doubt has of late 

 years been cast upon Lamarck's doctrine of the 

 hereditary transmission of acquired characters, it 

 remains as impossible as ever it was to question the 



