Edison works eighteen hours a day and only "rests" through sleep some four hours out of the twenty four. I wager that if he were put at work in his own plant, under the direction of a foreman, performing regular, monotonous tasks, he would break down under the strain of such long hours and would have to "rest" twice as much as he does now. His work satisfies him, and every new detail he perfects, every novelty he initiates, vouchsafes him a powerful ego gratification. Napoleon, too, could perform incredible feats of muscular activity and endurance after which four hours' sleep were sufficient to rest him. His life was for many years a continuous round of ego gratifications, won at the cost of great exertions, it is true, but proclaiming to him and the world his almost unrestricted power and luck. One is forced to the conclusion that a desire for rest is a desire, not for decreased activity but for increased activity. I shall make this point clear through a simile. The manufacturer who "attends to business" must, in order to succeed, "concentrate" on a few subjects and exclude all others from his mind. He may for a few hours think of nothing but, let us say, a certain grade of woollens, certain machinery, a certain customer and perhaps a certain engineer and some financial problem connected with those four thoughts. He must therefore exclude from his mind at the time, thoughts of playing golf, buying new clothes, going to the theatre, renting an apartment, repairing his motor car, thoughts of meals, women, card playing, and many other thoughts which are clamouring for admission to consciousness because they all represent human cravings. In his relaxed moments he will let all those other thoughts come to the surface. Which means that, what tired him, was the fact that he had to keep all those subjects down and allow only the other four to rise to consciousness. Mental rest consists in admitting ideas pell mell into consciousness without exercising any censorship on them. It consists in passing from a reduced but directed mental activity to an increased but undirected mental activity. In other words, rest is the free, normal, unimpeded functioning of the vagotonic nerves which upbuild the body and assure the continuance of the race. Ego and sex activities, mental and physical, are constantly struggling for admission to consciousness and for their gratification. They are held down, however, by the sympathetic nerves which play the part of a safety device, moderating or inhibiting the vagotonic activities whenever the latter might endanger the personality.