The first concerns population. Population, like commodities, may be superabundant or it may be insufficient. What regulates its numbers? “The number of people,” Smith replies, “depends upon the demand of society, and this is how it works. Among the proletariat, generally speaking, children are plentiful enough. It is only when wages are very low that poverty and misery cause the death of many of them; but when wages are fairly high several of them manage to reach maturity.” “It deserves to be remarked, too,” he continues, “that it necessarily does this as nearly as possible in the proportion which the demand for labour requires. If this demand is continually increasing, the reward of labour must necessarily encourage in such a manner the marriage and multiplication of labourers as may enable them to supply that continually increasing demand by a continually increasing population. If the reward should at any time be less than what was requisite for this purpose, the deficiency of hands would soon raise it; and if it should at any time be more, their excessive multiplication would soon lower it to this necessary rate. The market would be so much under-stocked with labour in the one case, and so much over-stocked in the other, as would soon force back its price to that proper rate which the circumstances of the society required. It is in this manner that the demand for men, like that for any other commodity, necessarily regulates the production of men; quickens it when it goes on too slowly, and stops it when it advances too fast.”[186]