College grades afford a means of recording intellectual efficiency directed toward particular problems. With no apparent change in bodily conditions the same student frequently increases his efficiency a hundred per cent. The increase seldom has an injurious effect on health, but is merely evidence of the fact that he has suddenly wakened up and is applying energies which before were undiscovered. A slow walk for a single mile leaves many persons ``dragged out'' and exhausted, but a brisk walk of the same or a greater distance results in invigoration and recuperation. Likewise the droning over an intellectual task results in exhaustion, while vigorous treatment whets the appetite for additional problems. This swift, decisive attack on problems was <p 17> the method of Edward H. Harriman, who crowded into ten years the railroad achievements of an extraordinary lifetime. Decisions involving expenditure of many millions of dollars were arrived at so quickly as to seem off-hand, even reckless. In reality, they were the products of brief periods of intense application in which he reviewed all the conditions and elements involved, and forged his conclusion, as it were, at white heat. Back of each decision was exact and thorough knowledge of the physical and traffic conditions of each of his railroads. In the case of the Union Pacific, at least, he gained this mastery by patient, intensive study of each grade and curve and freight-producing town on its 1800 miles of track. The inhabitant of the torrid zone upon moving to a northern climate is severely affected by the chill of the atmosphere. The discomfort may last for days or months, but he becomes acclimated and is able to withstand the cold without serious discomfort. Likewise the inhabitant of a cool climate feels exhausted <p 18> by the heat of the torrid zone. In some cases he is unable to accustom himself to the change, but in many instances the acclimatization follows rapidly and leaves the individual well fortified against the dangers of excessive heat. Persons who have accustomed themselves to stimulants of any sort are completely depleted if they are unable to get the special form to which they have been accustomed. This holds true for tobacco, morphine, coffee, and many other forms of stimulants actually indulged in by many persons. If they are able to resist the temptation and deny themselves the stimulant, the period of exhaustion soon disappears and the subject may even lose all craving for that which formerly seemed essential to his very existence.