We have seen (b) that, in order to make a valid contract, it is necessary that there should be true, full and free consent of the parties; that is, consent unimpeachable as having been induced by mistake, misrepresentation, fraud, duress or undue influence. In dealing with mistake, as the cause of the want of consent, let us first eliminate the ease where the parties are really agreed but there is an error in the expression of their consent. In that case the error may generally be rectified. And we will discuss the subject of mistake as a ground for the rectification of the agreement, after we have considered it as giving rise to a claim for obtaining the avoidance or resisting the specific performance of the contract.

(a) Above, pp. 1, 2.

(b) Above, p. 2.

Now in all cases where the validity of a contract is impeachable on the ground of mistake, misrepresentation, fraud, duress or undue influence, there is an apparent consent of the parties. At first sight, their minds are met. But the case of mistake appears to differ from the other grounds above mentioned for setting aside the contract in this, that where there is mistake there never has been an intention common to both parties - the one has never given any real assent to what has been proposed by the other. Apparently, the one did an act which amounted in the law to contract: but his mind did not accompany his overt act; he never intended to do what, to all outward appearance, he did. But in the case of misrepresentation, fraud, duress or undue influence, a consent, which is to a certain extent a true consent, accompanies the act, which is outwardly manifested. The party misled by misrepresentation or fraud, or coerced or influenced, really means to agree with the other in the terms expressed; he truly intends to contract: only he would not have been willing to do so, if he had known the truth with regard to the fact, as to which he was misled by the other, either innocently or fraudulently, or if he had not been forced or influenced. The consequence of this distinction is very marked. Contracts induced by any mistake, which the mistaken party is cot estopped from asserting, are altogether void from the beginning; there never has been from the outset any agreement between the parties. But contracts induced by misrepresentation, fraud, etc, are voidable only. This contrast is perhaps best illustrated in the case of negotiable instruments. A bill of exchange or promissory note, which was given or made by some averrable mistake, excluding true consent, is void, and is therefore of no more avail in the hands of a holder in due course than a forged bill or note (c). But a bill or note procured to be made by fraud, though voidable by the giver or maker as against the party who misled him, is valid in the hands of a holder in due course, against whom the plea of fraud cannot prevail (d).

Where the contract is impeachable for mistake, misrepresentation, fraud, etc, there is always an apparent consent.

No real assent in the case of mistake.

In the case of misrepresentation, fraud, etc, there is real consent induced by belief in nonexistent facts or by coercive influence.

Mistake makes the contract void from the beginning.

Contracts induced by misrepresentation, fraud, etc, are voidable only.

"With regard to mistake as a ground for avoiding a contract altogether, the rule of the common law appears to be that, in order to make a valid contract, there must be true consent of the parties; so that, where owing to a mistake the parties' minds are not at one, the contract is void; that is to say, there is no agreement at all (e).

The rule is that, where owing to mistake the parties' minds are not at one, there is no contract.

(c) Foster v. Mackinnon, L. R. 4 C. P. 704; Lewis v. Clay, 67 L. J. Q. B. 224. As to forged instruments, see next Chapter, Sec. 1, at end.

(d) Stat. 45 & 46 Vict. c. 61, ss. 29, 30, 38; Tatam v. Haslar, 23 Q. B. D. 345; Clutton v. Atten-borough, 1895, 2 Q. B. 30G, 707; 1897 A. C. 90.

(e) Smith v. Hughes, L. R. 6 Q. B. 597, 607, 609; Benjamin on Sale, 42, 2nd ed. The same rule appears to hold good as regards the conveyance of any property; if there be no true assent of the parties in parting with and accepting the thing assured, the conveyance is void. But as regards the conveyance of lands or goods, this rule is subject to the qualification that the assent of the alienee is presumed until the contrary be shown, and in the meantime (if the conveyance were duly made in accordant with the forms prescribed by law) the alienor is estopped from disputing the assurance. Thus if one disclaim a conveyance of lands or goods made to him, the conveyance is thenceforth void as from the time of its execution: but until disclaimer the estate or property passes to the alienee. See Bract, fo. 15 b, 16; Y. B. 7 Edw. IV. 20 (pl. 21), 29 (pl. 14); Thoroughgood's case, 2 Rep. 9; Butler and Baker's case, 3 Rep. 25a, 26b; Shep. Touch. 229, 267, 285;

And it seems that this rule may in some cases hold good, notwithstanding that the mistake be that of one party only, the other truly intending to contract in the terms expressed (f). The rule is, however, subject to the qualification, that "whatever be a man's real intention, if he manifests an intention to another party, so as to induce the latter to act upon it in making a contract, he will be estopped from denying that the intention as manifested was his real intention" (g). In other words, the rule requiring true consent of the parties to a contract is modified by the operation of the general rule of law that every man is taken to intend the natural and reasonable consequences of his own overt acts, including his spoken or written words; he is estopped from showing that what he really intended was something different from what a man of ordinary intelligence would naturally and reasonably infer from those acts or words (h). And this qualification is of enormous importance; indeed in practice the qualification overshadows the rule. For the instances, in which a person truly mistaken is estopped from proving his real intention, are so much more common than those in which there is no such estoppel, that when we come upon a case where a man's real intention may be set up to defeat an apparent expression of his consent, we are apt to regard it as exceptional (i).