Over thirty-five years ago Fehling1 showed a relationship between ovarian function and calcium metabolism by demonstrating the curative action of oophorectomy on osteomalacia following pregnancy. With the development in recent years of satisfactory microchemical methods for the estimation of the inorganic constituents in blood, calcium has been receiving ceaseless attention with a view to establishing the manner of its manifold operation in the animal economy. Among the many such studies, some have been directed toward investigations of the influence of the menstrual cycle on the concentration of calcium in blood.
We do not propose herein to discuss the literature pertinent to this topic, nor to undertake the recital of the many theories offered by investigators in explanation of their varied observations. The present status of the conclusions in this problem may be accepted as indicated in three recent publications, those by Rittmann,2 Schultze3 and Heyn and Haase.4 From these one