Population, laws of, cannot be comprised in a brief formula, 400. Vindication of Malthus, and of the general doctrine of his Essay on Population, 397, 400. If, as wealth increases, the number among whom it is to be divided increases more rapidly, absolute wealth may be greater, but individual wealth will be less, 401. Malthus has reduced the principle to the formula that population tends to keep on a level with the means of subsistence, 402. This principle not new; every writer on such subjects since Aristotle has proclaimed it, ib. Enunciated by Sir James Steuart thirty years before the appearance of the Essay on Population, ib., note. Nature has taken greater care of species than of individuals, in order to insure the perpetuity of races, 402. Instances of this in the vegetable kingdom, ib.; and in animals whose life is of a type more akin to vegetables, 402, 403. Advancing in scale of social life, means of reproduction bestowed with greater parsimony, ib. In the human species, reproductive faculty less powerful than in any other, ib. But, physically, man does not escape the law of a tendency to multiplication beyond the limits of space and nourishment, ib. Difference between the physiological power of multiplying and actual multiplication, ib. Malthus inquired in what period of time mankind would double, if space and food were unlimited, 404. But as this hypothesis is never realized, theoretical must be shorter than actual period, ib. Different rates of increase in different countries according to estimate of M. Moreau de Jonnès, 403. Such differences not the result of physiological causes, but of external obstacles, 404. New sources of local wealth lead invariably to increase of population, ib. Objections made to the theory of Malthus very illogical, ib. Nor are the arguments against his geometrical progression more conclusive, ib. Fixed on twenty-five years as the minimum period in which population may double itself, because this actually takes place in America, 405. Malthus merely asserts that it has a tendency to increase in a geometrical progression, ib. That this virtual power of multiplication will be restrained is just what Malthus contends for, ib. Restrained by preventive and repressive checks, 406. He was wrong in adopting the limit of twenty-five years, although it holds good in America, 406, 407. This mixing up of the virtual and the real has exposed him to be misunderstood and misrepresented, 406. Calculation by Euler of period of doubling, 407. Applying Euler's calculation to the facts stated by Moses, Hebrews who entered Egypt must have doubled in 14 years, ib. Absolute power of multiplication limited by obstacles, 408.