[Footnote 2: Endemann, _Studien_, vol. ii. pp. 49; Desbuquois, _op. cit._, p. 174.] [Footnote 3: II. ii. 77, 1.] [Footnote 4: _Ibid._] § 4. _The Just Price of Labour_. Particular rules were laid down for determining the just price of certain classes of goods. These need not be treated in detail, as they were merely applications of the general principle to particular cases, and whatever interest they possess is in the domain of practice rather than of theory. In the sale of immovable property the rule was that the value should be arrived at by a consideration of the annual fruits of the property.[1] The only one of the particular contracts which need detain us here is that of a contract of service for wages (_locatio operarum_). Wages were considered as ruled by the laws relating to just price. 'That is called a wage (_merces_) which is paid to any one as a recompense for his work and labour. Therefore, as it is an act of justice to give a just price for a thing taken from another person, so also to pay the wages of work and labour is an act of justice.'[2] Again, 'Remuneration of service or work ... can be priced at a money value, as may be seen in the case of those who offer for hire the labour which they exercise by work or by tongue.'[3] Biel insists that the value of labour is subject to the same influences as the value of any other commodity which is offered for sale, and that therefore a just price must be observed in buying it.[4] [Footnote 1: Caepolla, _de Cont. Sim._, 78; Carletus, _Summa Angelica_, lxv.] [Footnote 2: Aquinas, _Summa_, II. ii. 114, 1.] [Footnote 3: II. ii. 78, 2, ad. 3.] [Footnote 4: _Op. cit._, IV. xv. 10. Modern Socialists caricature the correct principle 'that labour is a commodity' into 'the labourer is a commodity'--a great difference, which is not sufficiently understood by many present-day writers. (See Roscher, _Political Economy_, s. 160.)]