[15] No doubt there may be a difference of opinion on this subject in France, where public opinion is too much exercised over the problem of depopulation. I agree with M. Varigny (``La Th<e'>orie du Nombre,'' _Revue des Deux Mondes_, Dec. 15, 1890) that the population of a country is not the sole, or even the principal consideration. Apart from physical characteristics (race), intellectual and moral qualities, and the productiveness of the soil on which M. Varigny dwells, we must take into account, as it seems to me, the unquestionable law by virtue of which the struggle for existence, amongst individuals as amongst nations, becomes gradually less vehement and direct. War, which is an everyday matter with savages, grows constantly more rare and difficult. The varying social and international conscience of civilised humanity is not to be neglected, and it must be reckoned with as a positive factor in considering the destiny of nations. Men continue to speak of the perils of war (in which numbers stand for a great deal, but are not the exclusive element) as though the social conscience of our own day were still the same as that of the Middle Ages. In several respects, on the other hand, the thinner population of France is one cause of its wealth, and therefore of its power. Germany has a more numerous, but also a poorer population. And I do not believe that the actual power of nations, on which their future depends, consists in loading a people with arms after enfeebling it by military expenditure, which from the year 1880 has indicated a distinct epidemic mania on the continent of Europe.