The plow is one of the most ancient and most valuable of man's inventions; but long before he existed the land was in fact regularly plowed, and still continues to be thus plowed by earthworms. It may be doubted whether there are many other animals which have played so important a part in the history of the world, as have these lowly organized creatures.

Even the humblest mammal's strong sexual, parental, and social instincts give rise to 'do unto others as yourself' and 'love thy neighbor as thyself'.

[Alexander von Humboldt was the] greatest scientific traveller who ever lived.

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

Blushing is the most peculiar and the most human of all expressions. Monkeys redden from passion, but it would require an overwhelming amount of evidence to make us believe that any animal could blush.

Delight itself, however, is a weak term to express the feelings of a naturalist.

It's an awful stretcher to believe that a peacock's tail was thus formed but ... most people just don't get it - I must be a very bad explainer