EFFECT OF MANGANESE ON CALCIFICATION OF BONE.

1. Young mice were maintained on a basal diet composed of meat, which is poor in both manganese and calcium. 2. The addition of small amounts (2.5-5.0mg./kg. of meat) of manganese improved weight gain and calcification of bone and decreased incorporation of injected radiocalcium into bone. 3. Prolonged treatment with larger amounts (10.0-25.0mg./kg. of meat) of manganese depressed growth, induced defective calcification of bone and increased incorporation of radiocalcium into bone.