In-depth studies have an influence on general ideas, whereas theories, in turn, in order to maintain themselves, push their spectators to search for new evidence. The mind's activity that is maintained by the debates about these works, is probably the source of the greatest joys given to man to experience on Earth.

The theory [of evolution] is a scientific mistake.

I may say that here, as in most cases where the operations of nature interfere with the designs of man, it is not by a direct intervention on our part that we may remedy the difficulties, but rather by a precise knowledge of their causes, which may enable us, if not to check, at least to avoid the evil consequences.

I now never make the preparations for penetrating into some small province of nature hitherto undiscovered without breathing a prayer to the Being who hides His secrets from me only to allure me graciously on to the unfolding of them.

There is no part of the country where in the summer you cannot get a sufficient supply of the best specimens. Teach your children to bring them in for themselves. Take your text from the brooks, not from the booksellers.

Embryology furnishes, also, the best measure of true affinities existing between animals.

The world has arisen in some way or another. How it originated is the great question, and Darwin's theory, like all other attempts, to explain the origin of life, is thus far merely conjectural. I believe he has not even made the best conjecture possible in the present state of our knowledge.