672 THE POPULAR SCIENCE MONTHLY. 



before our minds the vital questions of human fecundity, and of the 

 ability of the earth to sustain its increasing multitude of human inhab- 

 itants. But in reading the statistics of this subject our interest in it 

 redoubles. When we find men in all nations and in all ages pressing 

 sharply on the means of subsistence, the loss by famine quickly re- 

 placed by new food for famine, the ravages of war and pestilence rap- 

 idly obliterated by new-growing populations, and apparently nothing 

 but the pressure of sheer want and misery able to limit human fecun- 

 dity, we may well question if this is to be the continued destiny of 

 mankind, and if there is no possible limit to population within this 

 sharp boundary of distress. 



Nearly a century has elapsed since Malthus published his disheart- 

 ening researches on this subject, and his conclusions yet remain only 

 in part refuted. If it really be, as he declares, that population tends 

 to increase in a geometrical ratio, while the food-supply increases only 

 in an arithmetical ratio, his conclusion, that population has a constant 

 tendency to run ahead of subsistence, seems inevitable. Fortunately, 

 however, his hypothesis, so far, has been proved only by arguments, 

 not by irrefutable facts. The numbers of mankind, it is true, have 

 frequently passed the boundary which divides want from plenty. But 

 the other requirement of the Malthusian doctrine was not, in those 

 cases, attained. Food-production has never yet reached its limit, and 

 the suffering so far caused by want of food might have been entirely 

 obviated had the earth been fully cultivated. It may, however, be 

 claimed by disciples of Malthus that this fact has nothing to do with 

 the question, and that, when the utmost food-production has been 

 attained, population will still press beyond it to the starvation limit. 

 This argument we venture to dispute. The attainment of a great 

 food-production introduces certain conditions into the problem which 

 may give it an entirely different aspect. Such excessive production 

 will require, for instance, a marked advance in human intelligence, 

 and the replacement of much of the muscular labor of mankind by an 

 active mental labor. It is our purpose to consider what effect this 

 changed condition of the human race will have upon the increase of 

 population. It is easy to point to modern instances in which the rapid 

 increase of population has been checked without special exercise of 

 the starvation influence. The population of France, for instance, has 

 been almost stationary for many years, its increase being much below 

 the corresponding increase of wealth in that country. Thus France 

 furnishes a practical argument against the Malthusian hypothesis, and 

 shows that the growth of population may decline from other causes 

 than vice, misery, and disease. 



There exist, in fact, three separate checks to the increase of popu- 

 lation. These may be here classed as the physical, the mental, and 

 the physiological. The first and second of these have been fully con- 

 bidered by writers on political economy. The third has been barely 



