"The state of slavery is of such a nature that it is incapable of being introduced on any reasons, moral or political, but only by positive law, which preserves its force long after the reasons, occasion, and time itself, from whence it was created, is erased from the memory; it is of a nature that nothing can be suffered to support it but positive law." He referred to the contrary opinion of Lord Hardwicke, in October, 1749, as Chancellor: "That he and Lord Talbot, when Attorney and Solicitor General, were of opinion that no such claim, as here presented, for freedom, was valid." The weight of this decision is sought to be impaired, from the terms in which it was described by the exuberant imagination of Curran. The words of Lord Mansfield, in giving the opinion of the court, were such as were fit to be used by a great judge, in a most important case. It is a sufficient answer to all objections to that judgment, that it was pronounced before the Revolution, and that it was considered by this court as the highest authority. For near a century, the decision in Somersett's case has remained the law of England. The case of the slave Grace, decided by Lord Stowell in 1827, does not, as has been supposed, overrule the judgment of Lord Mansfield. Lord Stowell held that, during the residence of the slave in England, "No dominion, authority, or coercion, can be exercised over him." Under another head, I shall have occasion to examine the opinion in the case of Grace. To the position, that slavery can only exist except under the authority of law, it is objected, that in few if in any instances has it been established by statutory enactment. This is no answer to the doctrine laid down by the court. Almost all the principles of the common law had their foundation in usage. Slavery was introduced into the colonies of this country by Great Britain at an early period of their history, and it was protected and cherished, until it became incorporated into the colonial policy. It is immaterial whether a system of slavery was introduced by express law, or otherwise, if it have the authority of law. There is no slave State where the institution is not recognised and protected by statutory enactments and judicial decisions. Slaves are made property by the laws of the slave States, and as such are liable to the claims of creditors; they descend to heirs, are taxed, and in the South they are a subject of commerce.