The more one knows, the more one comprehends, the more one realizes that everything turns in a circle.

Beware of dissipating your powers; strive constantly to concentrate them.

The most difficult thing is what is thought to be the simplest; to really see the things which are before your eyes.

Nature reacts not only to physical disease, but also to moral weakness; when the danger increases; she gives us greater courage

Those who know nothing of foreign languages know nothing of their own.

Don't dissipate your powers; strive to concentrate them. Genius thinks it can do whatever it sees others doing, but it will surely repent of every ill-judged outlay.

Every solution of a problem is a new problem.