4 ON THE ORIGIN OF SPECIES 



best chance of making out this obscure problem. Nor 

 have 1 been disappointed ; in this and in all other 

 perplexing cases I have invariably found that our 

 knowledge, imperfect though it be, of variation under 

 domestication, afforded the best and safest clue. I may 

 venture to express my conviction of the high value of 

 such studies, although they have been very commonly 

 neglected by naturalists. 



From these considerations, I shall devote the first 

 chapter of this Abstract to Variation under Domestica- 

 tion. We shall thus see that a large amount of 

 hereditary modification is at least possible ; and, what 

 is equally or more important, we shall see how great is 

 the power of man in accumulating by his Selection 

 successive slight variations. I will then pass on to the 

 variability of species in a state of nature ; but I shall, 

 unfortunately, be compelled to treat this subject far too 

 briefly, as it can be treated properly only by giving 

 long catalogues of facts. We shall, however, be en- 

 abled to discuss what circumstances are most favourable 

 to variation. In the next chapter the Struggle for 

 Existence amongst all organic beings throughout the 

 world, which inevitably follows from the high geo- 

 metrical ratio of their increase, will be treated of. 

 This is the doctrine of Malthus, applied to the whole 

 animal and vegetable kingdoms. As many more 

 individuals of each species are born than can possibly 

 survive ; and as, consequently, there is a frequently 

 recurring struggle for existence, it follows that any 

 being, if it vary however slightly in any manner profit- 

 able to itself, under the complex and sometimes varying 

 conditions of life, will have a better chance of surviving, 

 and thus be naturally selected. From the strong 

 principle of inheritance, any selected variety will tend 

 to propagate its new and modified form. 



This fundamental subject of Natural Selection will 

 be treated at some length in the fourth chapter ; and 

 we shall then see how Natural Selection almost in- 

 evitably causes much Extinction of the less improved 

 forms of life, and leads to what I have called Divergence 



