Let us not underrate the value of a fact; it will one day flower in a truth. It is astonishing how few facts of importance are added in a century to the natural history of any animal. The natural history of man himself is still being gradually written.

What wisdom, what warning can prevail against gladness? There is no law so strong that a little gladness may not transgress.

We are enabled to apprehend at all what is sublime and noble only by the perpetual instilling and drenching of the reality that surrounds us. We can never have enough of nature.

Some circumstantial evidence is very strong, as when you find a trout in the milk.

As for me, Abraham, Isaac, and Jacob are now only the subtlest imaginable essences, which would not stain the morning sky.

There are sure to be two prescriptions diametrically opposite.

There is a slumbering subterranean fire in nature which never goes out, and which no cold can chill.