Experiments with radiophosphorus and radiocalcium, administered to rats at different periods during the healing of fractures, show increased activity of the bone ash from the fractured bone as compared with the ash from homologous intact bone of the same animal.
Further investigations indicate that this effect is due mostly to an increased exchange of phosphorus and calcium between the plasma and the mineral substance of the bone. Measurements of the separated epiphysis indicate that this process involves the whole bone and the proximal epiphysis of the tibia as well.
Applying these results to the work of Roche and Mourgue, we are unable to confirm that the processes taking part in the healing of a fracture can also be found in the skeleton as a whole.