About five years ago, as the result of an experimental study on the value of elementary phosphorus in rickets, Miss Weinstock and I drew the following conclusions:1
The feeding of small amounts of elementary phosphorus to rats leads to the production of "a phosphorus band" at the epiphyses of the long bones. This consists of a transverse layer of dense compact osseous tissue, lying transversely, immediately adjacent to the proliferating cartilage. It is clearly visible on gross examination when the head of the bone is sectioned longitudinally, and stands out prominently in the roentgenographic picture. On microscopic examination, the band is found to consist of heavy trabeculae of bone, and to be limited to the subepiphyseal region of the shaft. As little as 0.007 mg. of phosphorus a day sufficed to bring about this change in the epiphyses.
Elementary phosphorus, whether given in small or in large doses, was