This growth in the number, speed of formation, permanence, delicacy and complexity of associations possible for an animal reaches its acme in the case of man.

The intellectual evolution of the race consists in an increase in the number, delicacy, complexity, permanence and speed of formation of such associations.

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.

All that exists, exists in some amount and can be measured.

From the lowest animals of which we can affirm intelligence up to man this type of intellect is found.

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

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.