Abstract
The rabbits used in this work were made rachitic with the McCollum diet 3143, which is high in calcium and low in phosphorus. The calcium is present, chiefly, in the form of calcium carbonate. Previous work with this diet has shown that after about 20 days the animals have more or less marked rickets, as evidenced by X-ray of the bones and by determination of the phosphorus in the serum.
The control animals were given the same diet with the addition of cod liver oil, about 1 cc. per 100 gm. of diet.
Calcium was given in the form of calcium chloride or calcium gluconate, both in the strength of 10 mg. Ca per cc. of solution, administered in one dose by stomach tube. The dose, both in controls and rachitic animals, varied from 25 mg. to 200 mg.
Blood was taken by heart puncture before the administration of calcium and again a few minutes afterwards.
The normal animals did not seem affected by the administration of calcium. Of the 24 rachitic animals, however, 12 died within 15 minutes of the administration. In these animals the blood was very thick and coagulated rapidly.
The cause of death in the rachitic animals was, probably, hypercalcemia. Before the administration of calcium both controls and rachitic animals showed, rather constantly, a serum calcium of about 12 mg. per 100 cc. After the administration of calcium one control animal showed a rise of the serum calcium to 19 mg., in the remaining controls the maximum rise was to 15 mg. In the rachitic animals quite a number showed extremely high values for serum calcium after calcium had been given by mouth.
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