Returning to "first principles," we find one useful exercise more or less within reach of all, without preparation or expense. We mean walking. The flexors and extensors of the legs, the broad muscles of the back and abdomen, and the slender and intricate bundles of fibres which support and steady the spine, are all gently exercised in locomotion. The respiration and circulation are moderately increased, and the blood aërated with fresh air. And all this can be had by simply stepping out of doors and setting in motion the muscular machinery, which moves so automatically that we soon become unconscious of its exertions. This, like all other exercise, should be taken at seasonable hours. We enter our protest against long walks before breakfast. To any but the robust they are positively injurious. The early riser and walker, unless long habituated and naturally vigorous, returns from his exercise draggled, faint, and exhausted, to begin the digestive labors of the day, and take his food with hunger rather than appetite. Abstinence has blunted the nicer perceptions of taste, and the jaded organs lose the power not only of discriminating flavors, but of knowing when to cry, "Enough!" "Brushing away the morning dew," like "love in a cottage," is very pretty in a book, but needs a solid basis in the stomach or in the larder. Running is a very healthy and an equally neglected exercise. Few vocations call upon us to fully expand the chest once a month. Running improves the wind, it is said. We give the name of long-winded to those who have a reserve of breathing capacity which they do not use in ordinary exertions, but which lies ready to carry them through extraordinary efforts without distress or exhaustion. Such persons breathe quietly and deeply. Running forms part of the training of the prize-fighter. It should be begun and ended at a moderate pace, as a knowing jockey drives a fast horse; otherwise, panting, and even dangerous congestion, may arise from the too sudden afflux of blood to the lungs. Nothing so pleasantly combines mental occupation with bodily labor as a pursuit of some one of the natural sciences, particularly zoölogy or botany. If our means allow a microscope to be added to our natural resources, the field of exercise and pleasure is boundlessly enlarged. To the labor of collecting specimens is joined the exhilaration of discovery; and he who has once opened the outer gate of the sanctuary of Nature finds in the study of her _arcana_ a pastime which will be a joy forever.