From my early youth I have had the strongest desire to understand or explain whatever I observed. ... To group all facts under some general laws.

One hand has surely worked throughout the universe.

I feel like an old warhorse at the sound of a trumpet when I read about the capturing of rare beetles.

Sympathy for the lowest animals is one of the noblest virtues with which man is endowed.

Of all the differences between man and the lower animals, the moral sense or conscience is by far the most important. This sense, as Mackintosh remarks, "has a rightful supremacy over every other principle of human action"; it is summed up in that short but imperious word "ought," so full of high significance. It is the most noble of all the attributes of man, leading him without a moment's hesitation to risk his life for that of a fellow-creature; or after due deliberation, impelled simply by the deep feeling of right or duty, to sacrifice it in some great cause.

I have long discovered that geologists never read each other's works, and that the only object in writing a book is a proof of earnestness.

I have watched how steadily the general feeling, as shown at elections, has been rising against Slavery. What a proud thing for England if she is the first European nation which utterly abolishes it! I was told before leaving England that after living in slave countries all my opinions would be altered; the only alteration I am aware of is forming a much higher estimate of the negro character.