The surface of the earth is not simply a stage on which the thousands of present and past inhabitants played their parts in turn. There are much more intimate relations between the earth and the living organisms which populated it, and it may even be demonstrated that the earth was developed because of them.

Embryology furnishes, also, the best measure of true affinities existing between animals.

The resources of the Deity cannot be so meagre, that, in order to create a human being endowed with reason, he must change a monkey into a man.

One naturally asks, what was the use of this great engine set at work ages ago to grind, furrow, and knead over, as it were, the surface of the earth? We have our answer in the fertile soil which spreads over the temperate regions of the globe. The glacier was God's great plough.

Select such subjects that your pupils cannot walk out without seeing them. Train your pupils to be observers, and have them provided with the specimens about which you speak. If you can find nothing better, take a house-fly or a cricket, and let each one hold a specimen and examine it as you talk.

The possibilities of existence run so deeply into the extravagant that there is scarcely any conception too extraordinary for Nature to realise.

A smattering of everything is worth little. It is a fallacy to suppose that an encyclopaedic knowledge is desirable. The mind is made strong, not through much learning, but by the thorough possession of something.