Littell's Living Age/Volume 147/Issue 1905/Muscular Development in Animals

M. Marangoni, in a paper communicated to the Academy of Sciences, attributes to the air-bladder of fishes another function besides that of regulating their buoyancy. He finds it so placed, and of such dimensions, as to render the fish unstable both as regards position and level; that if the animal makes no effort, it will either sink to the bottom or rise to the surface, and turn over, instead of swimming upright. He argues that this apparent inconvenience is really advantageous, both morally and physically. It keeps the fish on the alert, prevents it from contracting idle habits, and thereby renders it muscular and agile. He further maintains that the most active of terrestrial animals are those that have the least mechanical stability, and therefore must be continually engaged in keeping their balance by muscular adjustments, and he attributes their constitutional activity to the educating influence of this continuous effort. If M. Marangoni is right, the bicycle will inaugurate a new starting-point in human evolution. Ordinary human beings perform a wonderful feat in so co-ordinating the muscles, levers, and joints of the human body as to stand upright and move forward on so small a base as the soles of the feet; but the new variety of biped that performs rapid locomotion on a base of only half an inch width, while his centre of gravity is raised some two feet above that of normal foot-borne specimens, presents a case of balancing activity, effected by the co-operation of hands and feet, legs, arms, head, and body, without parallel in any other species of mammal, and he should evolve accordingly.