licit things – things that may be the object of a sales contract
Art. 1459. The thing must be licit and the vendor must have the right to transfer ownership thereof at the time it is delivered. (Civil Code)
The law requires that the object of the contract must be licit or lawful. In other words, the thing must be within the commerce of men. The thing may be illicit per se (by its nature) or per accidens (because of some provision of law declaring it illegal). If the subject matter of the sale is illicit, the contract is void and cannot be ratified. (see Comments and Cases on Sales, p. 25, 26 ).
Can X enter into a contract for the sale and purchase of a kidney?