He went to the bed, lifted up the chintz which then covered the frame, and found his old friend the hole. A nut had been supplied and he could no longer get his finger into it. He rang the bell and when the servant came asked for a bed-key. All this time he was rapidly acquiring the reputation of being a lunatic throughout the whole house, but the key was brought, and by the help of it he got the nut off. When he had done so, there, sure enough, by dint of picking with his pocket-knife, he found the missing five-pound note. See how the return of a given present brings back the presents that have been associated with it. Unconscious Association One morning I was whistling to myself the air “In Sweetest Harmony” from _Saul_. Jones heard me and said: “Do you know why you are whistling that?” I said I did not. Then he said: “Did you not hear me, two minutes ago, whistling ‘Eagles were not so Swift’?” I had not noticed his doing so, and it was so long since I had played that chorus myself that I doubt whether I should have consciously recognised it. That I did recognise it unconsciously is tolerably clear from my having gone on with “In Sweetest Harmony,” which is the air that follows it. Association If you say “Hallelujah” to a cat, it will excite no fixed set of fibres in connection with any other set and the cat will exhibit none of the phenomena of consciousness. But if you say “Me-e-at,” the cat will be there in a moment, for the due connection between the sets of fibres has been established. Language The reason why words recall ideas is that the word has been artificially introduced among the associated ideas, and the presence of one idea recalls the others. V Vibrations Contributions to Evolution To me it seems that my contributions to the theory of evolution have been mainly these: 1. The identification of heredity and memory and the corollaries relating to sports, the reversion to remote ancestors, the phenomena of old age, the causes of the sterility of hybrids and the principles underlying longevity—all of which follow as a matter of course. This was _Life and Habit_. [1877.] 2. The re-introduction of teleology into organic life which, to me, seems hardly (if at all) less important than the _Life and Habit_ theory. This was _Evolution Old and New_. [1879.] 3. An attempt to suggest an explanation of the physics of memory. I was alarmed by the suggestion and fathered it upon Professor Hering who never, that I can see, meant to say anything of the kind, but I forced my view on him, as it were, by taking hold of a sentence or two in his lecture, on _Memory as a Universal Function of Organised Matter_ and thus connected memory with vibrations. This was _Unconscious Memory_. [1880.]