The case regarded a mistake made by Mr. Hughes, a horse trainer, who bought a quantity of oats that were the same as a sample he had been shown.

Its wider proposition, not directly relevant to the facts of the case, and later substantially reduced, was that a consumer buying an item, such as "a horse", without a representation or warranty (any seller's statement or special term as to its condition) making his own assessment which "turns out unsound" cannot avoid, that is seek to obtain a refund on, the contract — see for example the largely consolidatory Consumer Rights Act 2015.

Mr. Smith, who was a farmer, brought him a sample of his oats, of which Hughes then ordered forty to fifty quarters at a fixed price.

Leaning in Mr. Smith's favour, they held that the question was not merely whether the parties were at consensus ad idem (meeting of the minds), but what they had communicated by their conduct and words to one another.

Mr. Smith was held to be under no duty to inform Mr. Hughes of his possible mistake about the kind of oats, reaffirming the old idea of caveat emptor (buyer beware).

I take the true rule to be, that where a specific article is offered for sale, without express warranty, or without circumstances from which the law will imply a warranty—as where, for instance, an article is ordered for a specific purpose—and the buyer has full opportunity of inspecting and forming his own judgment, if he chooses to act on his own judgment, the rule caveat emptor applies.

It only remains to deal with an argument which was pressed upon us, that the defendant in the present case intended to buy old oats, and the plaintiff to sell new, so the two minds were not ad idem; and that consequently there was no contract.

This argument proceeds on the fallacy of confounding what was merely a motive operating on the buyer to induce him to buy with one of the essential conditions of the contract.

The defendant believed the oats to be old, and was thus induced to agree to buy them, but he omitted to make their age a condition of the contract.

And I also agree that where a specific lot of goods are sold by a sample, which the purchaser inspects instead of the bulk, the law is exactly the same, if the sample truly represents the bulk; though, as it is more probable that the purchaser in such a case would ask for some further warranty, slighter evidence would suffice to prove that, in fact, it was intended there should be such a warranty.

The jury were directed that, if they believed the word “old” was used, they should find for the defendant—and this was right; for if that was the case, it is obvious that neither did the defendant intend to enter into a contract on the plaintiff's terms, that is, to buy this parcel of oats without any stipulation as to their quality; nor could the plaintiff have been led to believe he was intending to do so.