Under certain circumstances, in periods of distress or under bad climatic condition, or if the soil yields too poor a return, Nature herself tends to check the increase of population in some countries and among some races, but by a method which is quite as ruthless as it is wise. It does not impede the procreative faculty as such; but it does impede the further existence of the offspring by submitting it to such tests and privations that everything which is less strong or less healthy is forced to retreat into the bosom of tile unknown. Whatever survives these hardships of existence has been tested and tried a thousandfold, hardened and renders fit to continue the process of procreation; so that the same thorough selection will begin all over again. By thus dealing brutally with the individual and recalling him