In the struggle for survival, the fittest win out at the expense of their rivals because they succeed in adapting themselves best to their environment.

The main conclusion arrived at in this work, namely that man is descended from some lowly-organised form, will, I regret to think, be highly distasteful to many persons. But there can hardly be a doubt that we are descended from barbarians.

But then with me the horrid doubt always arises whether the convictions of man's mind, which has been developed from the mind of the lower animals, are of any value or at all trustworthy. Would any one trust in the convictions of a monkey's mind, if there are any convictions in such a mind?

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

...for the shield may be as important for victory, as the sword or spear.

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.

The season of love is that of battle. The roots of these fights run deep.