286 THE ORIGIN OF SPECIES 



to the possessor. la each well-stocked country natural 

 selection acts through the competition of the inhabitants, 

 and consequently leads to success in the battle for life, 

 only in accordance with the standard of that particular 

 country. Hence the inhabitants of one country, generally 

 the smaller one, often yield to the inhabitants of another 

 and generally the larger country. For in the larger coun- 

 try there will have existed more individuals and more 

 diversified forms, and the competition will have beea 

 severer, and thus the standard of perfection will have 

 been rendered higher. Natural selection will not neces- 

 sarily lead to absolute perfection; nor, as far as we can i 

 judge by our limited faculties, can absolute perfection be 

 everywhere predicated. 



On the theory of natural selection we can clearly un- 

 derstand the full meaning of that old canon in natural 

 history, "Natura non facit saltum." This canon, if we 

 look to the present inhabitants alone of the world, is not 

 sti-ictly correct; but if we include all those of past times, 

 whether known or unknown, it must on this theory be 

 strictly true. f 



It is generally acknowledged that all organic beings 

 have been formed on two great laws — Unity of Type and 

 the Conditions of Existence. By unity of type is meant 

 that fundamental agreement in structure which we see in 

 organic beings of the same class, and which is quite 

 independent of their habits of life. On my theory, unity 

 of type is explained by unity of descent. The expression 

 of conditions of existence, so often insisted on by the 

 illustrious Cuvier, is fully embraced by the principle of 

 natural selection. For natural selection acts by either 

 now adapting the varying parts of each being to iti 



