The physical variety of exuberance, once won, makes easy the winning of the mental variety. This, when it is almost isolated from the other kinds, is what you enjoy when you soar easily along over the world of abstract thought, or drink delight of battle with your intellectual peers, or follow with full understanding the phonographic version of some mighty, four-part fugue. To attain this means work. But if your body is shouting for joy over the mere act of living, mental calisthenics no longer appear so impossibly irksome. And anyway, the discipline of your physical training has induced your will to put up with a good deal of irksomeness. This is partly because its eye is fixed on something beyond the far-off, divine event of achieving concentration on one subject for five minutes without allowing the mind to wander from it more than twenty-five times. That something is a keenness of perception which makes any given fragment of nature or human nature or art, however seemingly barren and commonplace, endlessly alive with possibilities of joyful discovery--with possibilities, even, of a developing imagination. For the Auto-Comrade, your better self, is a magician. He can get something out of nothing. At this stage of your development you will probably discover in yourself enough mental adroitness and power of concentration to enable you to weed discordant thoughts out of the mind. As you wander through your mental pleasure-grounds, whenever you come upon an ugly intruder of a thought which might bloom into some poisonous emotion such as fear, envy, hate, remorse, anger, and the like, there is only one right way to treat it. Pull it up like a weed; drop it on the rubbish heap as if it were a stinging nettle; and let some harmonious thought grow in its place. There is no more reckless consumer of all kinds of exuberance than the discordant thought, and weeding it out saves such an amazing quantity of _eau de vie_ wherewith to water the garden of joy, that every man may thus be his own Burbank and accomplish marvels of mental horticulture.