American Publishing Company v. Fisher
In American Publishing Company v. Fisher, 166 U.S. 464, 468, 17 S.Ct. 618, 619, 41 L.Ed. 1079 (1897), the Court said:
"Now, unanimity was one of the peculiar and essential features of trial by jury at the common law. No authorities are needed to sustain this proposition. Whatever may be true as to legislation which changes any mere details of a jury trial, it is clear that a statute which destroys this substantial and essential feature thereof is one abridging the right. It follows, therefore, that the court erred in receiving a verdict returned by only nine jurors, the others not concurring."