This standing position as now explained is physiologically correct as a primary factor in the act of walking. The weight is thrown largely upon the rear foot, and thus enables the other knee to be bent and the forward foot to be lifted; at the same time the ankle of the rear foot should be bent so that the whole body is inclined slightly forward, thus allowing the propelling force of gravitation to be brought into play. The whole physiology of walking is, indeed, perfectly simple when once these fundamental principles are understood. It is really resolved into the primary movements of allowing the body to incline forward from the ankle on which the weight is supported and then preventing oneself from falling by allowing the weight to be taken in turn by the foot which has been advanced. This method, simple as it may appear, is not, however, the one usually adopted. The mechanical disadvantage displayed in what is known as a “rolling gait,” for instance, a gait which is common enough, is absolutely impossible when the instructions given are carefully followed. And the effect upon the whole mechanical mechanism of the person concerned is shown by the fact that when the co-ordinating principles brought about by this method are established, there is a constant tendency for the torso to lengthen, whereas the usual tendency—due to faulty standing position and the incorrect co-ordinations which follow—is for the torso to shorten. Nearly every one I examine or observe in the act of walking, employs unnecessary physical tension in the process in such a way that there is a tendency to shorten the spine and legs, by pressing—if I may so put it familiarly—down through the floor instead of, as it were, lightening that pressure by lengthening the body and throwing the weight forward and moving lightly and freely. In consequence of the “shortening” and “pressing down” just referred to, the civilised peoples are becoming more and more flat-footed. The properly co-ordinated person employs a due amount of tension in such a way that the tendency of the spine and legs is to lengthen, and the equilibrium is such that the undue pressure through the floor is absent and there is a lightness and freedom in the movements of such a person that is most noticeable. The person who is flat-footed has only to establish these conditions to restore the natural arch of the flatfoot.