The Calcium and Inorganic Phosphorus Con- Tent of the Blood Serum of Swine

The object of this study was to ascertain the normal content of calcium and inorganic phosphorus in the blood serum of swine at various ages, and to determine the effect of a high and a low calcium diet on the amount of these elements. Bohstedt and his associates (5) ^ noted differences in these constituents in the blood of pigs when the calcium : phosphorus ratio varied greatly in the rations fed. Loeffel et al. (14-) found wide differences between the maximum and minimum content of these two elements in the blood of the pig, and stated that the blood plasma of animals receiving the direct rays of the sun were higher in these elements than those maintained in the absence of direct sunlight. Hughes and Hart (10) reported an average content in the blood serum of swine of 11.77 mg of calcium and 8.53 mg of inorganic phosphorus in 103 samples taken at random in the California Experiment Station herd. Bethke, Edgington, and Kick (2) showed the serum calcium and inorganic phosphorus of pigs about 200 days of age to be 11.1 and 6.4 mg, respectively (average of lots 4, 5, 6, 7, 8, 9, and 10 of the third experiment). The average of some of the figures reported by Dunlop {6) are serum calcium, 11.32 mg and inorganic phosphorus in whole blood, 6.93 mg (average of 56 determinations of blood taken from hogs weighing from 50 to 200 pounds, in experiment 4, groups 1, 2, 3, and 6). Howland and Kramer (9) collected, summarized, and published much of the early work up to and including that of 1921 on the calcium and inorganic phosphorus content of the serum of plasma of domestic animals. In this summary it was shown that three workers had reported, respectively, the calcium content to be 8.7, 9.6, and 9.7 mg and one had reported the inorganic phosphorus to be 2.3 mg, in 100 cc of the blood serum of the pig. PROCEDURE