262 Darwin, and after Darwtn. 
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 asa 
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! 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 battle for life where only 
one in a thousand survives P 
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 awhole. 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, considcrable doubt has of late 
years been cast upon Lamarck’s doctrine of the 
hereditary transmission of acguircd characters, it 
remains as impossible as ever it was to question the 
