Dogs get lost hundreds of times and no one ever notices it or sends an account of it to a scientific magazine.

The un-conscious distortion of the facts is almost harmless compared to the unconscious neglect of an animal's mental life until it verges on the unusual and marvelous.

He who learns and runs away, lives to learn another day.

Just as the science and art of agriculture depend upon chemistry and botany, so the art of education depends upon physiology and psychology.

The dog, on the other hand, has few or no ideas because his brain acts in coarse fashion and because there are few connections with each single process.

It will of course, be understood that directly or indirectly, soon or late, every advance in the sciences of human nature will contribute to our success in controlling human nature and changing it to the advantage of the common wheel.

Whatever exists at all exists in some amount. To know it thoroughly involves knowing its quantity as well as its quality.