sides attached to the bones of the spine; and the breast-bone, or sternum, to which the ribs are attached in front. The ribs incline downwards with the spine, so that when we bend forward the capacity of the chest is diminished, and breathing hampered; from this come pallor, general debility, and diseases of the chest. The muscles of the back counteract the action of those of the chest in maintaining the erect position of the body, to preserve which no less than five layers of powerful muscles along the spine only are engaged. The spine is a highly flexible column, made up of a number of bones called vertebræ, united by cartilages and ligaments, and movable in all directions by the action of the overlying muscles. In childhood the spine is most liable to yield and become weak or deformed at the neck and loins, for the neck has to support the weight of the head, and the loins that of the internal organs of the body. In early infancy the muscles of these parts have not attained the strength necessary for the performance of these duties. The new-born infant's head falls forward, or from side to side, and requires to be carefully supported, lest the neck should be dislocated. Even quite tiny babies are unfortunately often carried in a sitting position, when they of course stoop forward, the head drooping, and the arms hanging forward beyond the centre of gravity; these drag on the shoulders, which are further rounded, while the strain on the muscles of the back is increased; and if the practice is persisted in, a permanent deformity results from it. Further,
