The English courts long ago declared it to be a rule of law to prevent perpetuities that no estate in lands could be created which was not to commence within the compass of a life or lives of persons then existing, with an exception intended to favor a minor heir. American courts accepted this rule, but some of them construed it as meaning that no estate in lands could be created which was to continue after the expiration of such a period. This construction was shown by Professor John C. Gray, in a work on "Perpetuities," to be unwarranted, and since its publication the cases which had proceeded on that basis have been generally treated as erroneous. The nature of a legal presumption, also, had been misconceived by several American courts. It had been treated as evidence of facts.[Footnote: Coffin _v._ United States, 156 United States Reports, 432.] Professor J. B. Thayer, in his "Preliminary Treatise on Evidence,"[Footnote: Pages 337, 566-575.] argued so forcibly against this view that in at least one State a decision in which it had been taken has been formally overruled.[Footnote: Vincent _v._ Mutual Reserve Fund Life Association, 77 Connecticut Reports, 281, 291; 58 Atlantic Reporter, 963.] The Court of Appeals of New York once held in a carefully prepared opinion that a railroad might be built along the shore of a navigable river, under authority from the State, without first making compensation to the riparian proprietors, whose access to the waters might thus be obstructed.[Footnote: Gould _v._ Hudson River Railroad Co., 6 New York Reports, 522.] In a text-book written by Chief Justice Cooley, this decision was justly criticised,[Footnote: Cooley on Constitutional Limitations, 670.] and not long after the publication of that work it was formally overruled.[Footnote: Rumsey _v._ New York and New England Railroad Co., 133 New York Reports, 79; 30 Northeastern Reporter, 654; 15 Lawyers' Reports Annotated, 618.] It is safe to say that its fate was largely the result of the comments thus made by a distinguished jurist, whose only motive could be to maintain the integrity and consistency of legal science. The general doctrine of the courts, which is commonly expressed by the rule "_stare decisis_," was never better stated than by Chief Justice Black of Pennsylvania, in these words: When a point has been solemnly ruled by the tribunal of the last resort, after full argument and with the assent of all the judges, we have the highest evidence which can be procured in favor of the unwritten law. It is sometimes said that this adherence to precedent is slavish; that it fetters the mind of the judge, and compels him to decide without reference to principle. But let it be remembered that _stare decisis_ is itself a principle of great magnitude and importance....