To write well is to think well, to feel well, and to render well; it is to possess at once intellect, soul, and taste.

Hold on; hold fast; hold out. Patience is genius.

The cat is the only animal which accepts the comforts but rejects the bondage of domesticity.

Let us investigate more closely this property common to animal and plant, this power of producing its likeness, this chain of successive existences of individuals, which constitutes the real existence of the species.

All the work of the crystallographers serves only to demonstrate that there is only variety everywhere where they suppose uniformity ... that in nature there is nothing absolute, nothing perfectly regular.

One can descend by imperceptible degree from the most perfect creature to the most shapeless matter, from the best-organised animal to the roughest mineral.

Writing well is at one and the same time good thinking, good feeling, and good expression; it is having wit, soul, and taste, all together.