Not one change of species into another is on record ... we cannot prove that a single species has been changed.

Whenever I have found that I have blundered, or that my work has been imperfected, and when I have been contemptuously criticised, and even when I have been overpraised, so that I have felt mortified, it has been my greatest comfort to say hundreds of times to myself that 'I have worked as hard as I could, and no man can do more than this.'

How fleeting are the wishes and efforts of man! how short his time! and consequently how poor will his products be, compared with those accumulated by nature during whole geological periods. Can we wonder, then, that nature's productions should be far 'truer' in character than man's productions; that they should be infinitely better adapted to the most complex conditions of life, and should plainly bear the stamp of far higher workmanship?

Besides love and sympathy, animals exhibit other qualities connected with the social instincts which in us would be called moral.

Ignorance more frequently begets confidence than does knowledge.

It has been a bitter mortification for me to digest the conclusion that the "race is for the strong" and that I shall probably do little more but be content to admire the strides others made in science.

The most energetic workers I have encountered in my world travels are the vegetarian miners of Chile.