It is perfectly clear that children are more numerous in the back settlements of America than in the maritime states, not because unoccupied land makes people prolific, but because the most prolific people go to the unoccupied laud. Mr. Sadler having, as he conceives, fully established his theory of population by statistical evidence, proceeds to prove, “that it is in unison, or rather required by the principles of physiology.” The difference between himself and his opponents he states as follows:-- “_In pursuing this part of my subject, I must begin by reminding the reader of the difference between those who hold the superfecundity of mankind and myself, in regard to those principles which will form the basis of the present argument. They contend, that production precedes population; I, on the contrary, maintain that population precedes, and is indeed the cause of, production. They teach that man breeds up to the capital, or in proportion to the abundance of the food, he possesses; I assert, that he is comparatively sterile when he is wealthy, and that he breeds in proportion to his poverty; not meaning, however, by that poverty, a state of privation approaching to actual starvation, any more than, I suppose, they would contend, that extreme and culpable excess is the grand patron of population. In a word, they hold that a state of ease and affluence is the great promoter of prolificness: I maintain that a considerable degree of labour, and even privation, is a more efficient cause of an increased degree of human fecundity._” To prove this point he quotes Aristotle, Hippocrates, Dr. Short, Dr. Gregory, Dr. Perceval, M. Villermi, Lord Bacon, and Rousseau. We will not dispute about it; for it seems quite clear to us that if he succeeds {240}in establishing it he overturns his own theory. If men breed in proportion to their poverty, as he tells us here,--and at the same time breed in inverse proportion to their numbers, as he told us before,--it necessarily follows that the poverty of men must be in inverse proportion to their numbers. Inverse proportion, indeed, as we have shown, is not the phrase which expresses Mr. Sadler’s meaning. To speak more correctly, it follows, from his own positions, that, if one population be thinner than another, it will also be poorer. Is this the fact? Mr. Sadler tells us, in one of those tables which we have already quoted, that in the United States the population is four to a square mile, and the fecundity 5,22 to a marriage, and that in Russia the population is twenty-three to a square mile, and the fecundity 4.94 to a marriage. Is the North American labourer poorer than the Russian boor? If not, what becomes of Mr. Sadler’s argument?