5. _Population increased at an unprecedented rate throughout Christendom in the nineteenth century, but the pace is now slackening._ The nineteenth century saw a great increase in the food-supplies available for Europe. The resources of the American continent were hardly touched until the great Western movement of population began and new agencies of transportation brought American fields thousands of miles nearer to European markets. The improvement of machinery and of other economic equipment in Europe likewise aided to increase production rapidly. Population followed, though not with equal step. Europe had a population of 200,000,000 in 1800, nearly 400,000,000 in 1900. The increase in England was from 12 to 18 per cent, each decade; it had 8,000,000 in 1800 and 30,000,000 in 1900. The United States had 5,000,000 at the beginning of the century and 75,000,000 at the close, an increase of over 30 per cent, each decade. Recently there has been a notable decline in the rate of increase in all the countries of Europe. France is already at the stationary stage, and England probably will have reached it by the middle of the century. The rate of increase by decades has fallen in America from thirty-three to twenty-four since the Civil War. Though the movement of the population is still upward, large classes are stationary or declining in numbers. [Sidenote: Conclusion] Population should increase more slowly than wealth and resources if progress is to go on. It has done so in the past century, and there is no probability of a too rapid increase in Christendom in the near future. A stationary or declining population, while not desirable, is not an impossibility. But this does not destroy the significance of the fact that there is inherent in humanity a great potential power of increase, the realization of which would be disastrous, the control of which is an important and ever-present condition of the social welfare. CHAPTER 22 CONDITIONS FOR EFFICIENT LABOR § I. OBJECTIVE PHYSICAL CONDITIONS [Sidenote: Subjective and objective factors of efficiency] 1. _The efficiency of labor, in its broadest sense, is its ability to render services or produce things that minister to welfare._ The efficiency of labor is a resultant of many influences. In part it depends on the physical and mental powers of men; in part on things outside of the worker that either stimulate and strengthen him, or give him more favorable conditions in which to work. These are respectively the subjective and the objective factors of efficiency. In its broader sense, therefore, the phrase "efficiency of labor" implies any and every influence that makes for a larger and better supply of goods. [Sidenote: Bounty and goodness of productive agents affect the output of labor]