Worms have played a more important part in the history of the world than humans would at first suppose.

The love of a dog for his master is notorious; in the agony of death he has been known to caress his master, and everyone has heard of the dog suffering under vivisection, who licked the hand of the operator; this man, unless he had a heart of stone, must have felt remorse to the last hour of his life.

I always make special notes about evidence that contridicts me: supportive evidence I can remember without trying.

I cannot persuade myself that a beneficient and omnipotent God would have designedly created...that a cat should play with mice.

Till facts are grouped & called there can be no prediction. The only advantage of discovering laws is to foretell what will happen & to see bearing of scattered facts.

Although I am fully convinced of the truth of the views given in this volume under the form of an abstract, I by no means expect to convince experienced naturalists whose minds are stocked with a multitude of facts all viewed, during a long course of years, from a point of view directly opposite to mine... I look with confidence to the future, to young and rising naturalists, who will be able to view both sides of the question with impartiality.

With mammals the male appears to win the female much more through the law of battle than through the display of his charms.