Possibilities are like the wings of birds; they allow man to soar and to climb to the heavens. And facts are like the atmosphere against which those wings must beat, and without which the soaring bird will surely plummet back to earth.

It is not accidental that all phenomena of human life are dominated by the search for daily bread - the oldest link connecting all living things, man included, with the surrounding nature.

Men are apt to be much more influenced by words than by the actual facts of the surrounding reality

Appetite, craving for food, is a constant and powerful stimulator of the gastric glands.

When the dog is repeatedly teased with the sight of objects inducing salivary secretion from a distance, the reaction of the salivary glands grows weaker and weaker and finally drops to zero.

Science demands from a man all his life. If you had two lives that would not be enough for you. Be passionate in your work and in your searching.

Do not become archivists of facts. Try to penetrate to the secret of their occurrence, persistently search for the laws which govern them.