Experiments on albino rats indicate that, following complete intrapelvic severance of the femoral, obturator and sciatic nerves, the growth in length of the inactivated tibia continues at a normal rate. The denervated bone also retains its sensitivity to the growth-promoting effect of somatotrophic hormone (STH) and to the growth-inhibitory effect of a variety of agents, such as dihydrotachysterol, cortisol and estradiol. The characteristic pathologic changes normally produced in bones by an excess of dihydrotachysterol or vitamin A are likewise not prevented by central denervation. On the other hand, the morbid lesions characteristic of bone lathyrism are greatly diminished following central denervation; presumably, these changes depend upon the functional activity of the legs. The experiments also indicate that the atrophy of a muscle (triceps surae), that follows severance of its motor nerves, can be further enhanced by certain compounds which produce intense catabolism (e.g., dihydrotachysterol, cortisol, estradiol, thyroxin), and delayed by an anabolic hormone such as STH.