To accomplish great things, we must not only act, but also dream; not only plan, but also believe.
If the path be beautiful, let us not ask where it leads.
Until one has loved an animal a part of one's soul remains unawakened.
The whole art of teaching is only the art of awakening the natural curiosity of young minds for the purpose of satisfying it afterwards.
Nature has no principles. She makes no distinction between good and evil.