Montesquieu

“ Men are like plants which never flourish if they are not well cultivated: among poor people, the race declines and sometimes even degenerates.
France supplies a great proof of all this. During the late wars, the dread which all the youths had of being enrolled in the militia forced them to marry, and that at too tender an age and in the bosom of poverty. A great many children were born of these numerous marriages who are not now to be found in France, because poverty, famine, and disease carried them off. ”

“ They perish almost as rapidly as they are born: they never thrive: feeble and impotent, they die retail in a thousand ways, or are carried off wholesale by those frequent epidemics which poverty and bad diet always produce: those who escape attain the age of manhood without possessing its vigour, and waste away during the rest of their lives. ”

“ The propagation of the species is wonderfully aided by a mild government. All republics are a standing proof of this; especially Switzerland and Holland, which, with regard to the nature of the land, are the two worst countries in Europe, and which are yet the most populous. ”