The real influence of the intoxicants and narcotics in common use has been a matter of fierce and prolonged controversy. The most opposite opinions have been set forth with ability and earnestness; but the weight they would otherwise carry is lessened by their mutually contradictor-y character. Notwithstanding the great influence of the physician's authority, people are perplexed by the blessings and bannings bestowed upon tobacco and the various forms of alcohol.

What is the real influence of stimulants and narcotics upon the brain? Do they give increased strength, greater lucidity of mind and more continuous power? Do they weaken and cloud the intellect, and lessen that capacity for enduring a prolonged strain of mental exertion which is one of the first requisites of the intellectual life? Would a man who is about to enter upon the consideration of problems, the correct solution of which will demand all the strength and agility of his mind, be helped or hindered by their use? These are questions which are asked every day, and especially by the young, who seek in vain for an adequate reply. The student grappling with the early difficulties of science and literature, wishes to know whether he will be wiser to use or to abstain from stimulants.

The theoretical aspect of the question has perhaps been sufficiently discussed; but there still remains the practical inquiry,—"What has been the experience of those engaged in intellectual work?" Have men of science—the inventors, the statesmen, the essayists, and novelists of our own day—found advantage or the reverse in the use of alcohol and tobacco?

The problem has for years exercised my thoughts, and with the hope of arriving at data which would be trustworthy and decisive, I entered upon an independent inquiry among the representatives of literature, science, and art, in Europe and America. The replies were not only numerous, but in most cases covered wider ground than that originally contemplated. Many of the writers give details of their habits of work, and thus, in addition to the value of the testimony on this special topic, the letters throw great light upon the methods of the intellectual life.

To each writer, and especially to Dr. Alex. Bain, Mr. R. E. Francillon, Mark Twain, Mr. E. O'Donovan, Mr. J E. Boehm, Professor Dowden, the Rev. Dr. Martineau, Count Gubernatis, the Abbe Moigno, and Professor Magnus, who have shown hearty interest in the enquiry, I tender my best thanks for contributing to the solution of the important problem of the value of stimulants; also to Mr. W. E. A. Axon for suggestive and much appreciated help. I should, however, be glad of further testimonies for use in a second edition.

January, 1883.