In actions of assumpsit a count is frequently introduced in the declaration charging that the defendant promised to pay the plaintiff for money lent. To recover, the plaintiff must prove that the defendant received his money, but it is not indispensable that it should be originally lent. If, for example, money has been advanced upon a special contract, which has been abandoned and rescinded, and which cannot be enforced, the law raises an implied promise from the person who holds the money to pay it back as money lent.