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

The greatest marvel is not in the individual. It is in the succession, in the renewal and in the duration of the species that Nature would seem quite inconceivable. This power of producing its likeness that resides in animals and plants, this form of unity, always subsisting and appearing eternal, this procreative virtue which is perpetually expressed without ever being destroyed, is for us a mystery which, it seems, we will never be able to fathom.

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.

In Ireland, there are the same fossils, the same shells and the same sea bodies, as appear in America, and some of them are found in no other part of Europe.

Genius is only a greater aptitude for patience.

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

The discoveries that one can make with the microscope amount to very little, for one sees with the mind's eye and without the microscope the real existence of all these little beings.