From William Osler’s A Way of Life: An Address to Yale Students, Sunday evening, April 20th, 1913:

Control of the mind as a working machine, the adaptation in it of habit, so that its action becomes almost as automatic as walking, the end of education— and yet how rarely reached! It can be accomplished with deliberation and repose, never with hurry and worry. Realize how much time there is, how long the day is. Realize that you have sixteen waking hours, three or four of which at least should be devoted to making a silent conquest of your mental machinery.

Concentration, by which is grown gradually the power to wrestle successfully with any subject, is the secret of successful study. No mind however dull can escape the brightness that comes from steady application. There is an old saying, “Youth enjoyeth not, for haste;” but worse than this, the failure to cultivate the power of peaceful concentration is the greatest single cause of mental breakdown. Plato pities the young man who started at such a pace that he never reached the goal. One of the saddest of life’s tragedies is the wreckage of the career of the young collegian by hurry, hustle, bustle and tension the human machine driven day and night, as no sensible fellow would use his motor.…

A few hours out of the sixteen will suffice, only let them be hours of daily dedication in routine, in order and in system, and day by day you will gain in power over the mental mechanism, just as the child does over the spinal marrow in walking, or the musician over the nerve centres. Aristotle somewhere says that the student who wins out in the fight must be slow in his movements, with voice deep, and slow speech, and he will not be worried over trifles which make people speak in shrill tones and use rapid movements. Shut close in hour-tight compartments, with the mind directed intensely upon the subject in hand, you will acquire the capacity to do more and more, you will get into training; and once the mental habit is established, you are safe for life….

Four or five hours daily it is not much to ask ; but one day must tell another, one week certify another, one month bear witness to another of the same story, and you will acquire a habit by which the one-talent man will earn a high interest, and by which the ten-talent man may at least save his capital.

Steady work of this sort gives a man a sane outlook on the world. No corrective so valuable to the weariness, the fever and the fret that are so apt to wring the heart of the young.