It is essential that the normal rate of healing be definitely established before any attempt is made to determine the effect of varous conditions and substances on the rate of healing. Once this normal rate is established it should be comparatively easy to estimate the amount of variation produced by such factors as diet, incomplete mobilization of fractured bones, the injection or deposit of substances at the site of fracture and all the other procedures which have been advocated to increase the rate of healing in bone and prevent nonunion.
Although the results reported in this article appear to establish the normal time required for healing, it is proposed to recheck them with the results obtained in experiments on another series of animals, in which more factors are held constant, before this rate of healing is accepted as a standard with which to compare variations from the normal.
The method