Some effects of accelerating growth - II. Skeletal development

Abstract

The development of the skeletons of rats reared as described in the preceding paper has been studied in three ways, the appearance of the ossification centres and their maturation, the skeletal proportions, and the chemical composition of the femur and parietal bones. Animals which had grown more rapidly than the average had skeletons which were in all respects more mature at each age than those of animals which had grown more slowly. The skeleton, however, did not mature quite fast enough to keep pace with the rapid growth in weight, so that rapidly growing animals of the same body weight as their slow growing litter-mates, but younger in age, had femora which were shorter and contained less calcium, and their epiphyseal development was not so far advanced. The chemical development of the femur was appropriate to the length of the bone.