Abstract
The absorption of calcium through the intestinal mucosa of the chick has been shown to come under the influence of vitamin D within 2 to 4 hours after vitamin D administration. A technique is described for the measurement of calcium accretion and resorption rates in the toe bone of a chick. The effect of vitamin D on the rates of accretion and resorption was determined, and it is concluded that vitamin D affects the accretion rate, which in turn could bring about an increase in the resorption rate per bone. It cannot be stated whether the action of the vitamin D on the bone is direct or indirect.