rhythm," and if you only "make good" in your work, you will enjoy the strain and hurry, you will keep pace with the best of us, and you will get more out of yourself in a day in the city than you ever did in a week on the farm.

This change in degree of mental activity does not necessarily mean that you are making more of a success of life.

Your activities may be ill-directed. Your new-found powers may be misspent and dissipated.

But you are mentally more alert Your mental forces have been stimulated by the stirring environment.

And, mark this particularly, a number of mental pictures will pass across the screen of your consciousness today in the same time that one mental image formerly required.

Now, you have learned that with every idea catalogued in memory, there is wrapped up and stowed away an associated "feeling tone" and an associated impulse to some particular muscular action.

Assuming this, you must at once see that here is an explanation of your new-found energy.

Your quickened step, your new-found decisiveness of action, your more observant eye, your clear-cut speech instead of the former drawling utterance, your livelier manner, your freshened enthusiasm and enjoyment of life—all of these are but manifestations of a quickened intelligence.

They are the working out through the motor paths of mental impulses to muscular action.

And these impulses to muscular action come thronging into consciousness because the livelier environment brings about a more rapid reproduction of memory pictures.

And here comes a particularly striking fact. One would naturally suppose that the more energy a man consumed, and the faster he lived, the more quickly his vitality would be exhausted and the shorter his life would be.

As a matter of fact, by the divine beneficence of Providence, your organism is so ordered as to adapt itself within certain wide limits to the demands made upon it.

You may call into play all the stored-up resources of your being and still not stake everything upon a single throw. For the supply of mental energy is as inexhaustible as the reservoir of all past experience, while the supply of physical energy involved in brain and nerve activity is, like the immortal liver of Prometheus, renewed as fast as depleted.

Two sets of facts that have been established by elaborate scientific experiment will convince you of the truth of these propositions.

Professor Patrick, of the State University of Iowa, conducted some of these experiments. He caused three young men to remain awake for four successive days and nights. They were then allowed to go to sleep, the purpose of the experiment being to determine just how much time Nature required to recuperate from the long vigil. They were allowed to sleep themselves out, and all woke up thoroughly rested. Yet the one who slept the longest slept only one-third longer than his customary night's sleep.

You have doubtless had the same experience yourself many times. It all goes to show that if we are awake four times as long as usual, we do not make up for it by sleeping four times as long, but four times as soundly, as customary. The hard-working mechanic requires no more hours of sleep than the corner loafer, the active man of affairs no more than the dawdler.

The time of tissue repair is about the same with all men under all conditions. It is the rate of repair that varies with the demand that has been put upon the body.

Again, look at the same subject from the standpoint of food supply. On what you now eat and drink you have a certain average weight. Eat, digest and assimilate a larger quantity of food and your weight will increase. This increase will be greatest at the start and will gradually slow up until you shall have reached the point beyond which you can gain no more. Given the same hygienic conditions that you have been accustomed to, you will maintain yourself at the increased weight on the increased supply of food.

Now, all this involves clearly enough a greatly increased rate of activity on the part of the bodily organs of assimilation and repair. It is a situation on all fours with that of the countryman whose rate of brain activity has been stimulated by an increased mental demand.

No man will maintain that better, more nourishing and more liberal food rations, transformed into increased bodily tissue, with a consequent greater weight and greater muscular strength, would result in a loss of vitality or the shortening of a man's life.

Pygmies cannot become giants physically or intellectually. But as the puny youth can by systematic exercise broaden his frame and develop his muscles into at least a semblance of the athlete, and can then through his healthier appetite and his faster rate of repair maintain himself without effort at the new standard; so can the mentally inert call forth their reserves of energy and maintain a higher standard of activity and fruitfulness.

Few men live on the plane of their highest efficiency. Few search the recesses of the well-springs of power. The lives of most of us are passed among the shallows of the mind without thought of the possibilities that lurk within the deeper pools.

This accumulation of potential subconscious reserve energy is a result of the evolution of man and the growing complexity of his life.

No man could, if he would, respond to all the impulses to muscular action aroused in him by sense-impressions. It would be still less possible for him to respond to every impulse to muscular action awakened from the past with the remembered thought with which it is associated.

Desire, interest, attention and the selective will must pick and choose among these multitudinous tendencies to action.

Here, then, is another fact that has immediate bearing upon your ability to carry out any ambition you may have. Your every action is the net result of selection among a number of impulses and inhibitory forces or tendencies.

As a general thing, consciousness is made up of a number of conflicting ideas, each with its associated feeling and its impulse to action. Just what you do in any particular case depends upon what mental picture is strongest, is most vivid in consciousness, and thus able to overcome all contrary tendencies.

As life becomes more and more complex, the number and variety of our sensory experiences increase correspondingly. And so it comes about, that we have untold millions of sensory experiences, carrying with them the impulses to muscular response, none of which, on account of the multiplicity of conflicting ideas, is ever allowed to find release and actually take form in muscular