There is sound philosophy perhaps in this recommendation. Many persons have observed that the preliminary process of "composing the thoughts" is one which requires a little time and effort, especially where one comes to his subject from a period of exercise, or repose, or any other condition in which the brain has not been active. The functional activity of the brain depends on the copious supply of the arterial blood, its activity varying with that supply, increasing as that supply is greater, and relaxing when it is diminished. But unlike other organs of the body, the brain is densely packed in an unyielding cavity, and there must be room made for this increased volume of circulation whenever it takes place. This is accomplished, physiologists tell us, in the cerebro-spinal fluid, the quantity of which has been estimated at two ounces. This fluid is readily absorbed and as readily reproduced, and thus its quantity varies in a certain inverse proportion to the volume of the circulation of blood in the brain; and by this means an equality of pressure is secured throughout all the variations in the force of the circulation. The act of adjustment between this balancing fluid and the blood requires a little period for its completion, and therefore the brain cannot instantaneously be brought to its maximum action.
Hence, where the circulation has been diverted from the brain, and the proposed mental effort requires it to be vigorously revived in the brain, time must be allowed for this process of adjustment, and room must be made for the needed supply of blood; and perhaps a familiar demonstration in mathematics, which fixes the attention, and will instantly detect any delinquency of that faculty, may often be one of the best modes of employing this transition period, and aiding the change.
We may observe here the singular paradox, which we believe that the philosophy of the mind and the experience of the scholar equally establish, that what are usually called the heaviest or severest subjects of thought are the least exhausting to the thinker. How many students, like Chief-Justice Parsons, have been accustomed, when fatigued with the labor of deep research, or exhausted by continued train of thought upon one subject, to relax the mind with arithmetical or geometrical problems. Isaac Newton could, month after month, spend in the profoundest problems of pure mathematics twice as many hours in the day as Walter Scott could give to the composition of what we call light reading; and it will be found that mathematicians, theologians, and metaphysicians have been able to sustain more protracted labor, and with less injury, than have poets and novelists. There are not wanting reasons which aid us to understand this paradox, but we will not enter upon them here.
Irregularities of habit will doubtless disturb the action of the mind. The mental power that is thrown away and wasted by recklessness in this respect is incalculable. But there are variations in mental power in the midst of health, in the absence of fatigue, and under the most regular habits. Perhaps few authors have more carefully adapted their habits to their work, or ordered their method of life with a more quiet equality, than did Milton. He went to bed uniformly at nine o'clock.[C] He rose in the summer generally at four, and in winter at five. When, contrary to his usual custom, he indulged himself with longer rest, he employed a person to read to him from the time of his waking to that of his rising. The opening of his day was uniformly consecrated to religion. A chapter of the Hebrew Scriptures being read to him as soon as he was up, he passed the subsequent interval till seven o'clock in private meditation. From seven till twelve he either studied, listened while some author was read to him, or dictated as some friendly hand supplied him with its pen. At twelve commenced his hour of exercise, which before his blindness was usually passed in his garden or in walking, and afterward for the most part in the swing which he had contrived for the purpose of exercise. His early and frugal dinner succeeded, and when it was finished he resigned himself to the recreation of music, by which he found his mind at once gratified and restored. He played on the organ, and sang, or his wife sang for him. From his music he returned with fresh vigor to his books or his composition. At six he admitted the visits of his friends; he took his abstemious supper, of olives or some light thing, at eight; and at nine, having smoked a pipe and drank a glass of water, he retired. Yet in the midst of this clock-like regularity his labors were broken by frequent unfruitful seasons. Symmons says of him, that "he frequently composed in the night, when his unpremeditated verse would sometimes flow in a torrent, tinder the impulse, as it were, of some strange poetical fury; and in these peculiar moments of inspiration, his amanuensis, who was generally his daughter, was summoned by the bell to arrest the verses as they came, and to commit them to the security of writing.... Some days would elapse undistinguished by a verse, while on others he would dictate thirty or forty lines.... Labor would often be ineffectual to obtain what often would be gratuitously offered to him; and his imagination, which at one instant would refuse a flower to his most strenuous cultivation, would at another time shoot up into spontaneous and abundant vegetation." He seldom wrote any in the summer.
Cowper said that he composed best in winter, because then he could find nothing else to do but think; and he contrasted himself in this respect with other poets, who have found an inspiration in the attractive scenes of the more genial seasons.
The biographer of Campbell has given us the following anecdote with respect to the oft-quoted lines,
"'T is the sunset of life gives me mystical lore,
And coming events cast their shadows before."
The happy thought first presented itself to his mind during a visit at Minto. He had gone early to bed, and, still meditating on "Lochiel's Warning," fell fast asleep. During the night he suddenly awoke, repeating, "Events to come cast their shadows before"! This was the very thought for which he had been hunting the whole week. He rang the bell more than once with increasing force. At last, surprised and annoyed by so unseasonable a peal, the servant appeared. The poet was sitting with one foot in the bed, and the other on the floor, with an air of mixed impatience and inspiration. "Sir, are you ill?" inquired the servant. "Ill! never better in my life. Leave me the candle, and oblige me with a cup of tea as soon as possible." He then started to his feet, seized hold of his pen, and wrote down the happy thought, but as he wrote changed the words "events to come" into "coming events," as it now stands in the text. Looking at his watch he observed that it was two o'clock, the right hour for a poet's dream; and over his cup of tea he completed his first sketch of "Lochiel."
Nor is this capriciousness exclusively the attribute of the poetic Muse.
Calvin, who studied and wrote in bed, if he felt his facility of composition quitting him, as not unfrequently he did, gave up writing and composing, and went about his out-door duties for days, weeks, and months together. But as soon as he felt the inspiration again, he went back to his bed, and his secretary set to work forthwith.