Studies on the state of the serum calcium.

Abstract

In low phosphorus rickets, the animal is unable adequately to utilize its calcium in spite of the fact that the blood contains a normal amount of calcium. In low calcium rickets the total calcium of the blood is low but, as shown by the addition of the fat soluble organic factor, the diet supplies enough calcium to provide for a normal amount in the blood. These facts make it seem of importance to determine the ratio of diffusible and colloidal serum calcium in the blood in the two conditions. Three litters of rabbits were used, as indicated in Table I. The diffusible serum calcium was separated by negative pressure filtration through a collodion membrane as described by Moritz. The rabbits were fed through a stomach tube twice daily throughout the course of the experiment as in the studies of Goldblatt and Moritz. Litter I and Litter II were placed on a diet deficient in phosphorus and the fat soluble organic factor. Two animals of Litter I and three animals of Litter II served as controls and received five drops of cod liver oil daily. At the end of thirty days all animals of litter I were killed. The three experimental animals had developed severe rickets while the controls showed no evidence of rickets. Litter II were killed at the end of eighteen days. Two of the experimental animals had developed moderate rickets while the third showed only severe osteoporosis. The controls showed no evidence of rickets. Litter III received for 23 days a diet deficient in calcium as well as the fat soluble organic factor. One animal served as a control and received five drops of cod liver oil daily.