Owing to this struggle for life, any variation, however slight and from whatever cause proceeding, if it be in any degree profitable to an individual of any species, in its infinitely complex relationship to other organic beings and to external nature, will tend to the preservation of that individual, and will generally be inherited by its offspring.

Blushing is the most peculiar and most human of all expressions.

I trust and believe that the time spent in this voyage ... will produce its full worth in Natural History; and it appears to me the doing what little we can to increase the general stock of knowledge is as respectable an object of life, as one can in any likelihood pursue.

So in regard to mental qualities, their transmission is manifest in our dogs, horses and other domestic animals. Besides special tastes and habits, general intelligence, courage, bad and good tempers. etc., are certainly transmitted.

Why does man regret, even though he may endeavour to banish any such regret, that he has followed the one natural impulse, rather than the other; and why does he further feel that he ought to regret his conduct? Man in this respect differs profoundly from the lower animals.

As for a future life, every man must judge for himself between conflicting vague probabilities.

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.