Chemical studies1 have made it clear that the defective calcification of the bones in rickets is associated with a diminished concentration of the inorganic phosphorus or the calcium of the serum. Certain cases show only a low inorganic phosphorus content, and this is the rule in uncomplicated rickets; other cases show only a low concentration of calcium, the condition usually found when rickets is complicated by tetany; while still others may be associated with diminished concentrations of both these elements.
It has furthermore been demonstrated that these low concentrations of calcium and phosphorus are found only in the active stage of the disease, and that when rickets heals,2 either spontaneously or as the result of treatment, the values return to normal.
The more recent work of Howland and Kramer3 has shown that when the product of the calcium and phosphorus concentrations in the serum is below a
ORR WJ, HOLT LE, WILKINS L, BOONE FH. THE CALCIUM AND PHOSPHORUS METABOLISM IN RICKETS, WITH SPECIAL REFERENCE TO ULTRAVIOLET RAY THERAPY. Am J Dis Child. 1923;26(4):362–372. doi:10.1001/archpedi.1923.04120160075007