Assumpsit.

The mere fact of unfulfilled promise was not enough, in the eyes of
medieval English lawyers, to give a handle to the law. But injury caused
by reliance on another man's undertaking was different. The special
undertaking or "assumption" creates a duty which is broken by fraudulent
or incompetent miscarriage in the performance. I profess to be a skilled
farrier, and lame your horse. It is no trespass, because you trusted the
horse to me; but it is something like a trespass, and very like a
deceit. I profess to be a competent builder; you employ me to build a
house, and I scamp the work so that the house is not fit to live in. An
action on the case was allowed without much difficulty for such
defaults. The next step, and a long one, was to provide for total
failure to perform. The builder, instead of doing bad work, does nothing
at all within the time agreed upon for completing the house. Can it be
said that he has done a wrong? At first the judges felt bound to hold
that this was going too far; but suitors anxious to have the benefit of
the king's justice persevered, and in the course of the 15th century the
new form of action, called _assumpsit_ from the statement of the
defendant's undertaking on which it was founded, was allowed as a remedy
for non-performance as well as for faulty performance. Being an action
for damages, and not for a certain amount, it escaped the strict rules
of proof which applied to the old action of debt; being in form for a
kind of trespass, and thus a privileged appeal to the king to do right
for a breach of his peace, it escaped likewise the risk of the defendant
clearing himself by oath according to the ancient popular procedure.
Hence, as time went on, suitors were emboldened to use "assumpsit" as an
alternative for debt, though it had been introduced only for cases where
there was no other remedy. By the end of the 16th century they got their
way; and it became a settled doctrine that the existence of a debt was
enough for the court to presume an undertaking to pay it. The new form
of action was made to cover the whole ground of informal contracts, and,
by extremely ingenious devices of pleading, developed from the
presumption or fiction that a man had promised to pay what he ought, it
was extended in time to a great variety of cases where there was in fact
no contract at all.

Consideration.

The new system gave no new force to gratuitous promises. For it was
a