IN the early days of my friendship with Prof. Huxley--I think about 1854--an afternoon call on him quickly brought the suggestion--"Come upstairs; I want to show you something which will delight you--a fact that goes slick through a great generalization!" His ironical expression was prompted by his consciousness that being so much given to generalizing I should be disconcerted. He was dissecting the brain of a porpoise, and the anomalous fact he pointed out was that the porpoise has a brain of relatively immense size--a size seemingly out of all relation to the creature's needs. What can an animal leading so simple a life want with an organ almost large enough to carry on the life of a human being? Huxley (not then professor) had no solution of the difficulty to offer, and at the time there did not occur to me what I believe to be the solution.
There has grown up universally an identification of mind with intelligence. Partly because the guidance of our actions by thought is so conspicious, and partly because speech, which occupies so large a space in our lives, is a vehicle that makes thought pre-