The velocity curve of fibroplasia in the healing of wounds in young rats reached its end-point 3 days ahead of a similar curve for adults. Strength and fibroplasia were manifest 1 day sooner than in the adults. A study of the increments of the curve showed that the rate of fibroplasia during the accelerated phase was less in the young and that it lasted longer. Correspondingly, retardation appeared later and was less in amount than in the curve for the adult rats. The amount of retardation was even less than in the curve obtained for adults on a high protein diet, in spite of the fact that in this latter curve there was a definite increase in the rate of fibroplasia.
Healing in the young, therefore, is more rapid than in adults because fibroplasia begins earlier and is less retarded, not because the rate of fibroplasia is greater.
Growth of the young is not hindered by the process of wound healing.