Abstract
The amounts or sodium, potassium, magnesium, calcium and phosphorus in the plasma or 623 samples or bovine blood were determined. With the exception of calcium, all were above the lower normal limits. Of the samples, 23·4 per cent contained less than 8·5 mg/100 ml of calcium. It is suggested that calcium intake is likely to be on or the most pressing dietary problems as production of milk rises and that intake of other minerals may also become inadequate in the future.