ABSTRACT
Political and other non-economic changes modified the tastes of populations and made them less favorable to high fertility. The knowledge of contraception increased, as well as the inclination to practice it. The economic changes which were responsible for the high rate of increase in national income tended to hold natality down and eventually to depress it. In much of the world, mortality is less sensitive to changes in per capita income than it was formerly, though under some conditions it will continue to be sensitive to variations in economic circumstances. It is essential, when discussing division of labor with respect to a country's economy, to allow for its trading relations with other countries and its participation in international division of labor. For if a country elects to participate fully in international division of labor, it can achieve all the benefits of specialization with a smaller population than if it participates only partially.
