Of all the creatures that breathe and creep on the surface of the earth, none is more to be pitied than man.

Animals are good to think with.

Man is the only animal for whom his own existence is a problem which he has to solve and from which he cannot escape.

Man, when perfected, is the best of animals, but when separated from law and justice, he is the worst of all. 

Who hears the fishes when they cry?

There be beasts that, at a year old, observe more, and pursue that which is for their good more prudently, than a child can do at ten.

Happiness is a warm puppy.

An ape will be an ape, though clad in purple.

We call them dumb animals, and so they are, for they cannot tell us how they feel, but they do not suffer less because they have no words.

How like to us is that filthy beast the ape.

Who sleepeth with dogs shall rise with fleas.

Keep running after a dog, and he will never bite you.

Animals are in possession of themselves; their soul is in possession of their body. But they have no right to their life, because they do not will it.