This preservation of favourable variations and the destruction of injurious variations, I call Natural Selection, or the Survival of the Fittest. Variations neither useful nor injurious would not be affected by natural selection and would be left a fluctuating element.

In my most extreme fluctuations I have never been an atheist in the sense of denying the existence of a God ... I think that generally (& more and more so as I grow older) but not always, that an agnostic would be the most correct description of my state of mind.

My books have sold largely in England, have been translated into many languages, and passed through several editions in foreign countries. I have heard it said that the success of a work abroad is the best test of its enduring value. I doubt whether this is at all trustworthy; but judged by this standard my name ought to last for a few years.

You will be astonished to find how the whole mental disposition of your children changes with advancing years. A young child and the same when nearly grown, sometimes differ almost as much as do a caterpillar and butterfly.

A grand and almost untrodden field of inquiry will be opened, on the causes and laws of variation, on correlation of growth, on the effects of use and disuse, on the direct actions of external conditions, and so forth.

Man scans with scrupulous care the character and pedigree of his horses, cattle, and dogs before he matches them; but when he comes to his own marriage he rarely, or never, takes any such care.

It is not the biggest, the brightest or the best that will survive, but those who adapt the quickest.