"I have often said, and I repeat it, that the only thing in a Judge's decision binding as an authority upon a subsequent Judge is the principle upon which the case was decided: but it is not sufficient that the case should have been decided on a principle if that principle is not itself a right principle, or one not applicable to the case; and it is for a subsequent Judge to say whether or not it is a right principle, and, if not, he may himself lay down the true principle. In that case the prior decision ceases to be a binding authority or guide for any subsequent Judge, for the second Judge who lays down the principle in effect reverses the decision."