In an effort to ascertain the extent of climatic effects on the human organism in health and disease, we have studied its effect on such metabolic diseases as diabetes mellitus, pernicious anemia, exophthalmic goiter and Addison's disease. In these diseases there was found a distinctly lowered death rate in the warmer regions that show, in general, a depression of the metabolic rate by the heat. The people of these regions possess relatively low blood pressures, and have distinctly less angina pectoris than is found in the cooler countries.
Since the climatic effects mentioned are probably exerted mainly through the endocrine glands (pancreas, thyroid, suprarenals), it was deemed advisable to determine whether a similar depression was exercised on the sex glands. For this purpose the birth statistics of different cities, states and countries were obtained. The numbers of births in each month for a number of years were taken, the mean