We have much to hope from the flowers.

Depend upon it there comes a time when for every addition of knowledge you forget something that you knew before. It is of the highest importance, therefore, not to have useless facts elbowing out the useful ones.

It is a capital mistake to theorize before one has data.

The best way of successfully acting a part is to be it.

I said that he was my superior in observation and deduction. If the art of the detective began and ended in reasoning from an armchair, my brother would be the greatest criminal agent that ever lived. But he has no ambition and no energy. He will not even go out of his way to verify his own solutions, and would rather be considered wrong than take the trouble to prove himself right.

Some people's affability is more deadly than the violence of coarser souls.

Our ideas must be as broad as Nature if they are to interpret Nature.