At the meeting of the American Pediatric Society held in June, 1920, one of us, in discussing a paper by Park and Howland1 on the effect of cod liver oil on rachitic bones as demonstrated by the roentgenogram, reported that we had found the concentration of the inorganic phosphorus of the serum to be low in rickets. The amount was definitely increased following the administration of cod liver oil. The present communication represents the work on which these statements were based.
Rickets is a disease characterized by a deficient deposition of calcium salts in the bones themselves and in the intercellular cartilage of the epiphyses. Various views have been expressed and various theories advanced to explain the failure of deposition. We have approached the question from the standpoint of the inorganic chemical composition of the blood serum. Inasmuch as the salts of the bones consist preponderantly of calcium phosphate,