This is very justly stated in Mr. Mill’s “Elements of Political Economy,” ch. iv. sec. i. p. 219, 2d edit.: both Mr. Ricardo and Mr. Mill, indeed, fully allow the distinction between productive and unproductive labour. M. Say, though he calls the labour of the menial servant productive, makes a distinction between the labour which is productive of _material_ products and the labour which is productive of _immaterial_ products. Of the latter products he says, “En favorisant leur multiplication, on ne fait rien pour la richesse, on ne fait que pour la consommation.”—_Table Analytique_, liv. i. ch. 13. This is a most characteristic difference; and though I prefer the classification of Adam Smith, as more simple, I should allow that, on these principles, the causes of the wealth of nations may be clearly explained. But I own myself utterly at a loss to conceive how they can be explained, if all labour be considered as equally productive. Footnote 37: Elem. of Polit. Econ. part ii. p. 93. Footnote 38: Princip. of Polit. Econ., part iv. p. 409. Footnote 39: Princip. of Polit. Econ., part iv. p. 411. Footnote 40: Principles of Polit. Econ., part iii., pp. 313, 317. Footnote 41: Principles of Polit. Econ., part iii. p. 313. Footnote 42: Principles of Polit. Econ., part iii. p. 313. Footnote 43: Principles of Polit. Econ. part ii. p. 69. Footnote 44: Wealth of Nations, b. i. c. vi. Footnote 45: It must always be recollected, that the advance of a certain number of days’ labour necessarily involves the wages paid for them, however these wages may vary in quantity. But the essential advance is the quantity of labour, not the quantity of money or corn. Footnote 46: Principles of Polit. Econ., part iii. p. 223. This is a most remarkable passage to come from Mr. Macculloch, who, though he agrees with Mr. Ricardo in words, has, in reality, deserted him, and agrees in substance with Adam Smith. According to the new meaning, which Mr. Macculloch has given to the term profits—the quantity of labour required to produce a commodity, is precisely equal to the quantity of labour for which it will ordinarily exchange, and certainly not equal to what Mr. Ricardo meant by the quantity of labour bestowed upon it. Footnote 47: Principles of Polit. Econ., part iii, s. 1. p. 221. Footnote 48: A person who uses a term in a particular sense practically defines it in that sense. Mr. Macculloch sometimes makes what have hitherto always been considered as profits mean labour; and sometimes makes labour, when used simply without any adjunct, mean fermentation, vegetation, or profits. Footnote 49: Macculloch’s Principles of Polit. Econ., part ii. p. 189. Footnote 50: Id. p. 190. Footnote 51: