Warranty, in English law, is a promise to secure a person in the enjoyment of a right transferred to him. According to ancient rules of procedure, a person whose title was questioned might vouch another to warranty—i.e. call upon him to make good the guarantee he had given; the vouchee on his appearance stepped into the place of the original defendant. As applied to land the term is now obsolete, but in the mercantile law warranties are still of great importance. On a contract of sale, e.g., the general rule is caveat emptor—let the buyer look to himself; a person who sells a thing in its natural state, having no better means of information than the purchaser, is not taken to warrant the quality of the article; he is not liable to make good any defects unless he has been guilty of fraud or dishonest concealment. But where the purchaser has to rely on the vendor the law will generally imply a warranty. Thus, a person selling goods for a particular purpose is usually taken to warrant that they are suitable for that purpose; a dealer in provisions, for instance, warrants them to be wholesome and fit for food. If the goods are unsuitable, it sometimes happens that the purchaser has two courses open to him: he may reject the goods as not corresponding to the contract, or he may accept the goods and sue the vendor for damages for breach of warranty. On a sale by a manufacturer, he is taken to warrant that the goods are of his own manufacture, unless the usage of trade is to the contrary; on a sale by sample there is an implied warranty that the bulk corresponds to the sample in quality and condition. A seller is held to warrant his right to sell; if he is not in fact the owner of what he sells he may have to pay damages if the true owner claims the property from the purchaser; but a seller with a doubtful title may protect himself by agreeing to transfer such rights as he has. The rule of law is sometimes expressed by saying that a seller is not liable in respect of patent defects (i.e. such as the buyer might discover by the exercise of his own judgment), but only for latent defects (i.e. defects known to the vendor which the purchaser has no means of discovering). A warranty must of course be carefully distinguished from a mere expression of opinion about the thing sold. An agent or servant has no right to give a warranty unless he is authorised to do so. On the sale of a horse, the purchaser must make proper inquiry and investigation; if the horse turns out restive or unmanageable, he cannot recover damages unless the seller has given him an express warranty to the contrary.
Unsoundness in horses is a relative term, and difficult to define; but the rule is that, if at the time of sale the horse has any disease which either actually does diminish its natural usefulness so as to make it less capable of performing the work it is intended for, or which in an ordinary course may hereafter diminish its usefulness, or if either from disease or accident it has undergone any alteration of structure that either actually at the time does, or may in its ordinary course, diminish the animal's usefulness, such a horse is unsound. Veterinarians of experience recognise two conditions under the term sound, and two converse ones under that of unsoundness. The first is recognised under the appellation of 'legally sound,' and is thus defined by Baron Parke. 'I think the word sound means what it expresses—viz. that the animal is sound and free from disease at the time he is warranted.' Now experience is opposed to this, as many, perhaps the majority, of horses have evidence of disease or of the results or products of disease or accident in some part or parts of the body; or they may have some infirmity, such as being slight 'roarers' or whistlers, or have slight stringhalt, which renders them legally unsound. Such horses if warranted sound are returnable; but they may nevertheless be what is termed serviceably sound—that is to say, fit to perform the work for which they are bought. Or again, a horse may have a bone spavin; now a bone spavin is looked upon as a disease, and a spavined horse is considered unsound. But if he is free from lameness and have good hock action, in the opinion of many veterinarians he is serviceably sound. And pathological investigation has confirmed this view, for it has discovered that the enlargement—the bone spavin or exostosis—is composed of reparative material, by which the actual disease has been cured. Then again there are what are denominated 'hereditary unsoundnesses,' and the following are officially recognised by the R.A.S.E.: roaring and whistling, bone and bog spavins, side-bones and ring-bones, stringhalt, cataract, and navicular disease.
See Anson, Law of Contract; Chalmers, Sale of Goods; Oliphant, Law of Horses; and Ross Stewart, Law of Horses (1892). Guaranty (q.v.), etymologically the same word as warranty, has a different sense in law.