The true significance of the word _tends_ must not be overlooked, or a similar fallacy to that of Nitti's will occur, when he overlooked the significance of the term "power to multiply." It is perfectly true to say, that population _tends_ to press upon the limits of subsistence, and unrestrained by moral means or man's reason actually does so.
Some social writers appear to think that, if they can show that production has far outstripped population, that, in other words, population for the last fifty years at least has _not_ pressed upon the limits of food, Malthus by that fact is refuted.
Nitti says (Population and the Social System, p.

91), "But now that statistics have made such great progress, and the comparison between the population and the means of subsistence in a fixed period of time is no longer based upon hypothesis, but upon concrete and certain data in a science of observation it is no longer possible to give the name of law to a theory like that of Malthus, which is a complete disagreement with facts.

As our century has been free from the wars, pestilences and famines which have afflicted other ages, population has increased as it never did before, and, nevertheless, the production of the means of subsistence has far exceeded the increase of men." And later on (p.

114) he says "Malthus's law explains nothing just as it comprehends nothing.

Bound by rigid formulas which are belied by history and demography, it is incapable of explaining not only the mystery of poverty, but the alternate reverses of human civilization." Nitti's conclusions are based largely on the fact that while food supplies have become abundant and cheap, birth-rates have steadily and persistently declined.
No-one who has studied the economic and vital statistics of the last half century can fail to be impressed with the change that has come over the relative ratios of increase in population and food.
Bonar says (Malthus and his Work, p.