69 H. G. Wells has said that "every word of which a man is ignorant represents an idea of which he is ignorant." And it is impossible per- fectly to understand all things unless all things be first known. Understanding is the structuralization of knowledge. All impressions are disconnected, as the Babe of the Abyss is so terribly aware; and the Master of the Temple must sit for 106 seasons in the City of the Pyramids because this coordination is a tremendous task. There is nothing [)articularly occult in this doctrine concerning know- ledge and understanding. A looking-glass receives all impressions but coordinates none. The savage has none but the most simple associations of ideas. Even the ordinary civilized man goes very little further. All advance in thought is made by collecting the greatest possible number of facts, classifying them, and grouping them. The philologist, though perhaps he only speaks one language, has a much higher type of mind than the linguist who speaks twenty. This Tree of Thought is exactly paralleled by the tree of nervous structure. Very many people go about nowadays who are exceedingly " well- informed," but who have not the slightest idea of the meaning of the facts they know. They have not developed the necessary higher part of the brain. Induction is impossible to them.