a Vio, written in 1499. The author of this treatise divides
money-changing into three kinds, just, unjust, and doubtful. There
were three kinds of just change; _cambium minutum_, in which the
campsor was entitled to a reasonable remuneration for his labour;
_cambium per litteras_, in which the campsor was held entitled to a
wage (_merces_) for an imaginary transportation; and thirdly, when
the campsor carried money from one place to another, where it was of
higher value. The unjust change was when the contract was a usurious
transaction veiled in the guise of a genuine exchange. Under the
doubtful changes, the author discusses various special points which
need not detain us here.

Thomas da Vio then goes on to discuss whether the justifiable exchange
can be said to be a species of loan, and concludes that it can not,
because all that the campsor receives is an indemnity against loss
and a remuneration for his labour, trouble, outlay, and risk, which
is always justifiable. He then goes on to state the very important
principle, that in _cambium_ money is not to be considered a measure
of value, but a vendible commodity,[1] a distinction which Endemann
thinks was productive of very important results in the later teaching
on the subject.[2] The last question treated in the treatise is the
measure of the campsor's profit, and here the contract of exchange
is shown to be on all fours with every other contract, because the
essential principle laid down for determining its justice is the
observance of the equivalence between both parties.[1]

[Footnote 1: 'Numisma quamvis sit mensura et instrumentum in
permutationibus; tamen per se aliquid esse potest.' It is this
principle that justifies the treatment of _cambium_ in this section
rather than the next.]

[Footnote 2: _Studien_, vol. ii. p. 212.]

SECTION 2.--THE SALE OF THE USE OF MONEY

Sec. 1. _Usury in Greece and Rome_.

The prohibition of usury has always occupied such a large place in
histories of the Middle Ages, and particularly in discussions relating
to the attitude of the Church towards economic questions, that it is
important that its precise foundation and extent should be carefully
studied. The usury prohibition has been the centre of so many bitter
controversies, that it has almost become part of the stock-in-trade of
the theological mob orators. The attitude of the Church towards usury
only takes a slightly less prominent place than its attitude towa