Edible substances evoke the secretion of thick, concentrated saliva. Why? The answer, obviously, is that this enables the mass of food to pass smoothly through the tube leading from the mouth into the stomach.

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

Gradualness, gradualness, and gradualness. From the very beginning of your work, school yourself to severe gradualness in the accumulation of knowledge.

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

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.

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

One can truly say that the irresistible progress of natural science since the time of Galileo has made its first halt before the study of the higher parts of the brain, the organ of the most complicated relations of the animal to the external world. And it seems, and not without reason, that now is the really critical moment for natural science; for the brain, in its highest complexity-the human brain-which created and creates natural science, itself becomes the object of this science.