Note (return) — ORGANIC DIFFERENCES IN THE SEXES

Dr. Lloyd Jones has determined that between 17 and 45 years of age the specific gravity of the blood of women is lower than that of men. In old women the specific gravity rises above that of old men, and he suggests that their greater longevity is due to this.92 No doubt the greater longevity of women is to be associated with the rise in specific gravity of their blood, but this rise in the specific gravity of women after 45 years is consequent upon their anabolic constitution. High specific gravity in general is associated with abundant and rich nutrition; it falls in women during pregnancy, lactation, and menstruation, and when these functions cease it is natural that the constructive metabolic tendency on which they are dependent should show itself in a heightened specific gravity of the blood (i.e., greater richness), and in consequence greater longevity.