The increase of population keeps pace with the increase of food; and, indeed, such being the power of the generative force, it overpasses the means of subsistence, establishing a constant pressure upon them. Under these circumstances, it necessarily happens that a certain amount of destitution must occur. Individuals have come into existence who must be starved. As illustrations of the variations that have occurred in the population of different countries, may be mentioned the immense diminution of that of Italy in consequence of the wars of Justinian; the depopulation of North Africa in consequence of theological quarrels; its restoration through the establishment of Mohammedanism; the increase of that of all Europe through the feudal system, when estates became more valuable in proportion to the number of retainers they could supply. The crusades caused a sensible diminution, not only through the enormous army losses, but also by reason of the withdrawal of so many able-bodied men from marriage-life. Similar variations have occurred on the American Continent. The population of Mexico was very quickly diminished by two million through the rapacity and atrocious cruelty of the Spaniards, who drove the civilized Indians to despair. The same happened in Peru. The population of England at the Norman conquest was about two million. In five hundred years it had scarcely doubled. It may be supposed that this stationary condition was to some extent induced by the papal policy of the enforcement of celibacy in the clergy. The "legal generative force" was doubtless affected by that policy, the "actual generative force" was not. For those who have made this subject their study have long ago been satisfied that public celibacy is private wickedness. This mainly determined the laity, as well as the government in England, to suppress the monasteries. It was openly asserted that there were one hundred thousand women in England made dissolute by the clergy. In my history of the "American Civil War," I have presented some reflections on this point, which I will take the liberty of quoting here: "What, then, does this stationary condition of the population mean? It means, food obtained with hardship, insufficient clothing, personal uncleanness, cabins that could not keep out the weather, the destructive effects of cold and heat, miasm, want of sanitary provisions, absence of physicians, uselessness of shrine-cure, the deceptiveness of miracles, in which society was putting its trust; or, to sum up a long catalogue of sorrows, wants, and sufferings, in one term--it means a high death-rate. "But more; it means deficient births. And what does that point out? Marriage postponed, licentious life, private wickedness, demoralized society.