Article I. On the Nature of Sale and Purchase

The contract of sale and purchase can be defined as an onerous contract by which any thing whatever estimable by price is exchanged for a determinate sum of money, dominion being mutually transferred. - Cf. St. Alphonsus, n. 795. - Kenrick, n. 45. - Kent, Comment., vol. 2, part 5, lect. 39, n. 468, (4).

I say. For transferring the dominion of the thing sold, by natural law the delivery of the thing itself is not required, if the freely given consent is otherwise established. - But by positive law a distinction must be made. According to Roman law the dominion of the thing does not pass to the buyer unless delivery has already been made; indeed it is also required that the price be paid or offered by the buyer, or at least that either suretyship or credit be furnished concerning it; and if this is not done, the buyer indeed has a right to the thing, but not a right in the thing. But according to our law, if the thing sold has been designated and separated from the rest, dominion is transferred without delivery, although at least an inchoate and authentic payment of the price is required. For if a thing, even designated and separated, is sold without any payment of the price, it can be recovered by the seller while it is in transitu, as they say, to a buyer who is not solvent. Yet notwithstanding these things, among us, says Kenrick: "The risk of the thing does not ever seem to pass to the buyer unless it has in some manner been delivered. All things depend on the custom of merchants." - Cf. St. Alphonsus, nn. 795 and 796. - Kenrick, tract. 10, n. 50; and tract. 11, nn. 45 and 47. - Kent, Comment., vol. 2, part 5, lect. 39, nn. 492 and 496.

Question. Whether the seller is bound to disclose the defects of the thing?

Resp. He is certainly bound to disclose all substantial defects, both in themselves and relatively to the buyer's known end, or all those which make the thing another thing, or render it harmful or notably useless; but of itself he is not bound to show accidental and manifest defects, provided that he diminishes the price according to the proportion of the defect. The reason is that then no injury is done to the buyer, neither by reason of the price, which is diminished, nor by reason of the defect, which, if the buyer has not seen it, he ought to impute to himself. I said of itself, because there must be excepted, 1st. the case of a very rude buyer, because in respect to him the defect is considered hidden, and 2nd. the case in which the seller is specially questioned concerning such a defect. But if the defect is indeed accidental but hidden, again a distinction must be made; for if the seller is questioned, he is bound to disclose it; otherwise he commits fraud and the contract will be rescindable. But if no questioning is done, the contract will be wholly firm, but the price must be diminished according to the proportion of the defect. - Cf. St. Alphonsus, n. 823.