Even at the time at which no action could be brought in the king's courts upon a genuine implied contract it was, nevertheless, recognized as a source of legal rights for purposes other than of bringing an action to enforce it directly. The idea which we find here may be inconsistent with the ideas of legal rights entertained by such a writer as Austin, who insists that a legal right which can not be enforced has no existence. At the same time the idea is one which is found in every system of law which is developing. Between the stage at which the law of a given period declines to recognize certain rights and the later stage at which it enforces such rights directly there is frequently an intervening stage at which such rights can not be enforced directly, but are otherwise recognized and protected.1 If a party to a genuine implied contract acquired possession thereunder of personalty belonging to the adversary party, the common law gave him a lien, and he could retain possession of such property until he was paid a reasonable compensation for the work and labor furnished by him under the contract.2 While at this period of development an action could not be brought upon a genuine implied contract, an action could be brought upon an express promise by the party who was liable under the implied contract to perform his obligation, although the consideration for the new promise had already been furnished under circumstances which did not create any legal liability at the time.3 While at modern law we are able to explain this as a case in which the original transaction imposes an unliquidated liability which is merely liquidated by the subsequent contract of the party, such explanation could not be used at a time at which no liability could be enforced in the absence of an express promise. Cases of this sort were in part responsible for the theory that a past consideration was sufficient to support an express -promise.4 In this case we have an obligation growing out of a genuine implied contract upon which at a certain stage of our law no action could be brought, but which was a sufficient consideration for. a subsequent express promise which created a right which the law would enforce for all purposes and upon which an action could be brought.

1 Tilford v. French, 1 Lev. 113, 1 Sid. 160; 1 Kcb. 590, 635; Bosden v. Thinne, Yelv. 40.

2 Y. B. 3 Hen. VI, 36, pl. 33.

3 Bosden v. Thinne, Yelv. 40.

4 Bosden v. Thinne, Yelv. 40.

5 Tilford v. French, 1 Lev. 113, 1 Sid. 160, 1 Kcb. 509, 635.

6 Hodsden v. Harridge, 2 Williams Saunders, 64, c. case 9.