[9] “In its action on the system nicotine is one of the most powerful poisons known. A drop of it in a concentrated form was found sufficient to kill a dog, and small birds perished at the approach of a tube containing it.”—Wood’s _Materia Medica_. “Tobacco appears to chiefly affect the heart and brain, and I have therefore placed it among cerebral and cardiac poisons.”—Taylor’s _Treatise on Poisons_. [10] “Certain events occur in the brain; these give rise to other events, to changes which travel along certain bundles of fibers called nerves, and so reach certain muscles. Arrived at the muscles, these changes in the nerves, which physiologists call nervous impulses, induce changes in the muscles, by virtue of which these shorten contract, bring their ends together, and so, working upon bony levers, bend the arm or hand, or lift the weight.”—Professor Michael Foster. [11] The synovial membranes are almost identical in structure with serous membranes (page 176), but the secretion is thicker and more like the white of egg. [12] “Smoking among students or men training for contests is a mistake. It not only affects the wind, but relaxes the nerves in a way to make them less vigorous for the coming contest. It shows its results at once, and when the athlete is trying to do his best to win he will do well to avoid it.” Joseph Hamblen Sears, Harvard Coach, and Ex-Captain of the Harvard Football Team, Article in _In Sickness and in Health_. [13] “There is no profession, there is no calling or occupation in which men can be engaged, there is no position in life, no state in which a man can be placed, in which a fairly developed frame will not be valuable to him; there are many of these, even the most purely and highly intellectual, in which it is essential to success—essential simply as a means, material, but none the less imperative, to enable the mind to do its work. Year by year, almost day by day, we see men (and women) falter and fail in the midst of their labors; ... and all for want of a little bodily stamina—a little bodily power and bodily capacity for the endurance of fatigue, or protracted unrest, or anxiety, or grief.”—Maclaren’s _Physical Education_. [14] “One half the struggle of physical training has been won when a boy can be induced to take a genuine interest in his bodily condition,—to want to remedy its defects, and to pride himself on the purity of his skin, the firmness of his muscles, and the uprightness of his figure. Whether the young man chooses afterwards to use the gymnasium, to run, to row, to play ball, or to saw wood, for the purpose of improving his physical condition, matters little, provided he accomplishes that object.”—Dr. D. A. Sargent, Director of the Hemenway Gymnasium at Harvard University.