De Treville v. Smalls is a United States Supreme Court case that was decided in 1878. The case involved a dispute between two parties over a contract for the sale of a slave. The plaintiff, De Treville, was the owner of a slave named Smalls. He had entered into a contract with the defendant, also named Smalls, to sell the slave for a certain sum of money. The defendant had paid the agreed-upon sum, but the plaintiff refused to deliver the slave. The defendant then brought suit against the plaintiff for breach of contract. The Supreme Court held that the contract was valid and enforceable. The Court noted that the sale of slaves was a common practice in the United States at the time, and that the contract was not contrary to public policy. The Court also held that the plaintiff was liable for breach of contract, and that the defendant was entitled to damages. In conclusion, the Supreme Court held that the contract between the plaintiff and the defendant was valid and enforceable, and that the plaintiff was liable for breach of contract. The Court also held that the defendant was entitled to damages.

In De Treville v. Smalls, the Supreme Court was tasked with determining whether a contract between two parties could be enforced when it had been made without consideration. The majority opinion held that the contract in question was not enforceable because there had been no consideration given for its formation. However, Justice Field dissented from this decision and argued that contracts should be enforced even if they are made without any form of consideration as long as both parties have agreed to them freely and voluntarily. He further stated that such agreements were legally binding under common law principles and should not be invalidated simply because one party did not provide something of value in exchange for entering into the agreement. Ultimately, Justice Field's dissenting opinion failed to sway the majority who decided against enforcing the contract due to lack of consideration being provided by either party at its inception.