Whatever your career may be, do not let yourselves become tainted by a deprecating and barren scepticism.

It is not the germs we need worry about. It is our inner terrain.

Without theory, practice is but routine born of habit. Theory alone can bring forth and develop the spirit of invention. ... [Do not] share the opinion of those narrow minds who disdain everything in science which has not an immediate application. ... A theoretical discovery has but the merit of its existence: it awakens hope, and that is all. But let it be cultivated, let it grow, and you will see what it will become.

Chance favours a prepared mind.

The grandeur of the acts of men are measured by the inspiration from which they spring.

The greatest malfunction of spirit is to believe things.

Are the atoms of the dextroacid (tartaric) grouped in the spirals of a right-hand helix or situated at the angles of an irregular tetrahedron, or arranged in such or such particular unsymmetrical fashion? We are unable to reply to these questions. But there can be no reason for doubting that the grouping of the atoms has an unsymmetrical arrangement with a non-superimposable image. It is not less certain that the atoms of the laevo-acid realize precisely an unsymmetrical arrangement of the inverse of the above.