the money was deemed still to belong to the
creditor, as if the identical coins were merely in the debtor's custody.
The creditor sued to recover money, for centuries after the Norman
Conquest, in exactly the same form which he would have used to demand
possession of land; the action of debt closely resembled the "real
actions," and, like them, might be finally determined by a judicial
combat; and down to Blackstone's time the creditor was said to have a
property in the debt--property which the debtor had "granted" him.
Giving credit, in this way of thinking, is not reliance on the right to
call hereafter for an act, the payment of so much current money or its
equivalent, to be performed by the debtor, but merely suspension of the
immediate right to possess one's own particular money, as the owner of a
house let for a term suspends his right to occupy it. This was no road
to the modern doctrine of contract, and the passage had to be made
another way.

Action for debt.

In fact the old action of debt covered part of the ground of contract
only by accident. It was really an action to recover any property that
was not land; for the remedy of a dispossessed owner of chattels,
afterwards known as detinue, was only a slightly varying form of it. If
the property claimed was a certain sum of money, it might be due because
the defendant had received money on loan, or because he had received
goods of which the agreed price remained unpaid; or, in later times at
any rate, because he had become liable in some way by judgment, statute
or other authority of law, to pay a fine or fixed penalty to the
plaintiff. Here the person recovering might be as considerable as the
lord of a manor, or as mean as a "common informer"; the principle was
the same. In every case outside this last class, that is to say,
whenever there was a debt in the popular sense of the word, it had to be
shown that the defendant had actually received the money or goods; this
value received came to be called _quid pro quo_--a term unknown, to all
appearance, out of England. Nevertheless the foundation of the
plaintiff's right was not bargain or promise, but the unjust detention
by the defendant of the plaintiff's money or goods.

Modes of proof.

We are not concerned here to trace the change from the ancient method of
proof--oath backed by "good suit," _i.e._ the oaths of an adequate
number of friends and neighbours--through the earlier form of jury
tri