In the case of Susan Mayburry v. John M'Pherson Brien and others, the Supreme Court was asked to decide whether a deed given by an emancipated slave was valid. The appellant argued that since she had been freed from slavery, her deed should be considered valid under state law. However, the appellees argued that because she had not been legally declared free prior to giving the deed, it could not be enforced in court. After considering both sides of this argument, the Supreme Court ultimately ruled in favor of Mayburry and held that her emancipation did indeed make her deed enforceable under state law. This ruling established important precedent for future cases involving emancipated slaves who sought legal recognition for their deeds or other contracts they may have entered into while still enslaved.

In the case of Susan Mayburry v. John M'Pherson Brien and others, the Supreme Court was asked to decide whether a deed given by an infant should be considered valid or voidable. The majority opinion held that such deeds were invalid because infants are not legally capable of entering into contracts; however, Justice McLean dissented from this decision. He argued that if an infant had sufficient understanding to comprehend the nature and consequences of his actions when executing a deed, then it should be considered valid even though he is still technically classified as an infant in law. Furthermore, Justice McLean noted that there may have been circumstances where it would have been beneficial for both parties involved if such a contract had been allowed to stand despite its execution by an infant. Ultimately, while Justice McLean agreed with the majority's conclusion regarding infants being unable to enter into binding contracts due to their lack of legal capacity under common law principles, he believed that exceptions could exist depending on individual cases involving minors who possess enough knowledge and understanding about what they are doing when signing documents like deeds.