Let us examine briefly, as physiologists, the condition of the bones—in the recruit and young soldier under twenty years of age. At this period the embryo soldier has still ten years to pass, before the framework of his body has arrived at maturity. In the early state of the long bones—such as those which compose the arm and leg—the bone commences to grow in the middle of the shaft, and progresses towards either end. The shaft of the bone is thus formed. Large portions at either end of this shaft remain for variable periods of time in a soft cartilaginous growing state, till at last separate and distinct points of bony growth appear in them also. They become gradually converted into bone, and as bony processes, they remain separated for a time from the principal piece, by an intervening soft substance, which for the time being glues them to the shaft of the long bone. There are portions also on the ribs, where they hinge upon the spine, which at the age of eighteen have only commenced to develope from soft material into bone, and their mysterious transformation is not completed till the twentieth year of life. The ribs, therefore, are not fully grown till that age. The shaft of the arm-bone continues to increase in length till the twenty-fifth year of life; and so long as this change continues, a portion of soft vesicular and growing tissue intervenes between the shaft and the head of the bone. It is not till about the twentieth year of life that this soft substance is converted into bone, and the principal bone of the arm becomes consolidated. The lower end of the bone of the fore-arm, to which the hand is mainly fixed at the wrist-joint, is also at the age of eighteen still incomplete, but it is finished at about twenty years of age. The lower end of the other bone of the fore-arm also unites about the same time. Shortly after the twentieth year the head of the thigh bone, which forms part of the hip-joint, unites to the shaft, and the end which forms the knee-joint becomes united to the principal piece also. The lower ends of the two bones of the leg at the ankle-joint, likewise coalesce with the shafts between the eighteenth and twenty-fifth year. Again, the breast-bone is composed of five pieces; the fifth coalesces with the fourth soon after puberty, and the fourth with the third between twenty and twenty-five years of age, whilst the body, or greater piece of the breast-bone is usually not completed by the junction of the third to the second before the thirty-fifth or fortieth year. In fact, the process of ossification is constantly going on in various important joints, and until that work of nature is settled, the full strength of manhood has not been attained; to say nothing of another fact to be taken into account, the growth of the bones and the muscles in a due relation to each other.
We must now go a step further, and examine into the effects produced by excess of training upon other portions of the body. Take, for example, the frame-work of the chest, in the cavity of which are situated those organs which seem especially to suffer whenever the recruit and the young soldier are subjected to over-exertion. Next to the inspiration of bad air, the imperfect, or continuously obstructed inspiration of the chest, tends more than any other cause known to bring about disease of the lungs and heart. The influence of pressure in the unfinished condition of the bones is, therefore, of vital importance, and demands the most anxious and incessant consideration. As the twig is bent so will the branch grow. We have seen that till the twentieth year of life some ribs are still imperfect, being soft at their joint-ends where resistance and motion occur. They are still growing. The breast-bone in front is in a similar condition. The slightest reflection, therefore, will make it evident that a perpetual pressure upon these parts from before and from behind must exercise a material influence in moulding the future form of the chest. The cartilages of the ribs in front of the breast-bone ought to have full freedom to rise upward and advance forward at every inspiration, the diameter of the chest being naturally increased by every act of breathing. Any weight upon this portion of the human frame exerted when the bones are still growing, must necessarily tend to set the bones themselves in an unnatural direction. To maintain the vital capacity of the lungs, the capacity of the chest cavity from side to side must necessarily be increased; and at what cost? At the cost of the mal-formation of the chest. The capacity of the lungs goes on increasing with age and height, so that men from five feet to six feet high inspire from 174 to 262 cubic inches in a progressively ascending scale. Moreover, the growth of the heart goes on relatively to the growth of the body.
From all that has been said, the reader must have been convinced of one fact—the importance of attending to the co-relative conditions in a recruit of—age, height, and weight. If eighteen years of age is to be the minimum fixed for the enlistment of growing lads, then the height should be as near as possible five feet four inches, and the weight 112 pounds. A height below this average will prove to have been as a rule the result of defective feeding in early life, tending to the diminution of the normal rate of increase of the body. Under such circumstances, stunted development and diseased vital processes are the inevitable consequences. Constitutional tendencies of the future man are thus more or less certainly fixed at an early age; and although at eighteen the recruit may have no evident disease, yet a minimum height and weight will indicate a constitutional defect which requires only extraneous circumstances to develope. On the other hand, again, the excessive growth of the body generally, compared with the expansion and vital capacity of the lungs, becomes sufficiently obvious by the contrast of the tall body with the narrow and flat chest, in which the apices of the lungs approach close to each other. Generally in such cases the reparative organs are out of proportion to the body which has to be sustained. If the height of the soldier is the main qualification to be regarded in selecting men, age should be considered in accordance. If men five feet eleven inches or six feet are in request, they should not be less than twenty to twenty-five years old, and the weight should be about 160 to 180 lbs. The Romans understood