Chap. XIV392
A debt also arises by reason of a Purchase and Sale. When any person sells a thing to another, the price is due to the Vendor, and the thing contracted for to the Purchaser.393
But a purchase and sale are effectually perfected from the moment the price is settled between the contracting parties; provided possession of the thing purchased and sold be delivered,394 or that the price, either wholly, or in part, be paid, or, at least, that Earnest395 be given and received.396
But, in the two former cases, neither of the Contracting parties can by any means at his own option recede from the Agreement, unless for some just and reasonable cause; as, if the terms of the contract were, that either of the parties may with impunity retract within a certain period; then, indeed, either party may within the period prescribed avail himself of the terms of the Contract and recede, without being liable to any penalty: since it is, generally speaking, unquestionable that, Conventio legem vincit.397 Besides, if the Vendor sold the thing to the Purchaser as being sound and without fault,398 and the Purchaser can afterwards satisfactorily shew, that the thing at the time of the contract was not sound, but faulty, then, indeed, the Vendor shall be compelled to take back his property. But it is sufficient, if the thing was in a proper state, at the time of the Contract, whatever may afterwards happen to it. But I doubt, as to the period within which this should be proved, or complaint made concerning it, especially where there is no special Agreement. Where, however, Earnest only has been given, if the Purchaser would recede from the Contract, he may do so, with the loss of the Earnest. But if, in such case, the Vendor would retract, it is a question whether he can do so without incurring a penalty.399 It does not seem that he can; because he would then be in a better situation than the Purchaser. But, if it cannot be done with impunity, what punishment shall such conduct incur?400 The risk of the thing sold and purchased generally belongs to the person who has possession of it,401 unless it has been differently arranged.