Hurry generally implies lack of system in carrying out the routine of work, or the undertaking of more work than the individual can accomplish without injury to herself. Few things can more certainly muddle the brain and produce a sense of physical exhaustion than a sense of hurry. Without the sense of this insane driver with a lash in his hands standing over one, she can work more rapidly, with complete self-possession, and do more accurate and better work. The peculiar sense of being hurried has a direct benumbing physical effect, that can often be felt in the brain as distinctly confusing. =The Toxins of Fatigue.=—By speeding the machinery to the utmost, a strain is placed on nerves and muscles, and they are kept keyed up to the greatest possible tension. There is a natural pace that one can keep up; force the pace, and weariness results. A man can go for hours at the rate of five miles an hour; he can run at the rate of six miles an hour for quite a long while; but if he tries to run eight miles an hour, he will drop out very soon. The powers of endurance must be gradually developed, but no machine should ever be run at its utmost speed. By undue pressure, at any period of life, it is possible to use up energy that ought to have been spread out over long periods; and this is emphatically the case during adolescence; too heavy a drain is made on futurity, which means a serious breakdown, or, at least, premature old age. It has long been assumed that during the activity of muscles substances were produced which exerted a poisonous influence upon the muscle tissues. Exactly what these substances were was not known, but it was supposed that they were definite products of metabolism or tissue waste. It is a well-known phenomenon, observed during the training of athletes and soldiers, that prolonged and disciplined exercise makes it possible for individuals to support easily an amount of work which would prove exhausting or even fatal to the untrained. Increased work, under any circumstances, means increased metabolism, and consequently a more rapid accumulation of its products. A German investigator, Dr. Weichardt, has shown that if guinea-pigs were put upon a miniature treadmill and forced to run it until they dropped dead from exhaustion, a highly poisonous liquid could be pressed from their muscles, and that the injection of this liquid or extract into the veins of healthy guinea-pigs produced, when administered in small doses, rapid fatigue; whereas, larger doses caused death, accompanied by all the symptoms observed in the original animal during the process of mechanical tiring. On the other hand, liquid taken from unworked guinea-pigs had no such effect. Further, that if these little animals were put upon a treadmill and worked to just short of exhaustion, and then were given time to recuperate, as we say, the liquid or extract from their muscles had no such effect: it was quite harmless.