Vitality and beauty are gifts of Nature for those who live according to its laws.

One day the world will look upon research upon animals as it now looks upon research on human beings.

The truth of things is the chief nutriment of superior intellects.

O sleepers! what a thing is slumber! Sleep resembles death. Ah, why then dost thou not work in such wise as that after death thou mayst retain a resemblance to perfect life, when, during life, thou art in sleep so like to the hapless dead?

If you do not rest on the good foundation of nature, you will labour with little honor and less profit.

Anyone who invokes authors in discussion is not using his intelligence but his memory.

Man has much power of discourse which for the most part is vain and false; animals have but little, but it is useful and true, and a small truth is better than a great lie.