192 HARVARD LAW REVIEW. the plaintiff use due care?" but "Did he stop, look, and listen? " It has been objected that although the omission to look and listen may in a particular case be inconsistent with due care, and so require the setting aside of a verdict, it is a very different thing to declare that it must always be so; l and the Pennsylvania doctrine has been denied in many States. 2 But this doctrine, though per- haps an extreme illustration, is typical of the process as it is going on in every jurisdiction ; 3 and it comes from a court which vigor- ously asserts the " time-honored rule," that the court must not invade the province of the jury in deciding questions of negli- gence.* Closely connected with this subject is the growth of rules of pre- sumption, of one class of which Austin has said that " they are re- sorted to by the courts as a means of legislating indirectly." 5 These rules, in regard to the true nature of which there has been much con- fusion, have been accurately described as prima facie rules of law, operating upon certain specified facts, their effect being to say that when x is shown, and no more, it is to be taken as equal to y? The constant recurrence of similar states of fact, handled by the jury under the supervision of the court, leads to the growth of these prima facie rules, just as it gives rise to absolute rules fixing the legal standard of negligence, etc. Such and such facts, it is held, are sufficient to make a case for the plaintiff, and to shift the burden of proof. In the absence of further evidence a conversion or a sale may be taken as proved. Thus mere matter of evidence passes over into a rule of presumption. It would be easy to mul- tiply instances of such rules from every branch of the law. A well-known example is found in the law of prescription, which shows not only the growth of the judicial rule as to when an ori- gin beyond the time of legal memory would be presumed, but also the further step (a strong instance of judicial legislation) by which 1 It may perhaps fairly be answered that as a practical matter the benefit of the Pennsylvania rule in ninety-nine cases more than makes up for the hundredth case in which it works injustice to the plaintiff. 2 See, for example, Terre Haute R. Co. v. Voelker, 129 111. 540. 3 Mr. Justice Holmes in his Common Law, Lecture III., comments on this process, which he regards as a resuming by the court of a function, its own rather than an en- croachment on the sphere of the jury. An encroachment in the sense of an improper, or even an unnecessary, extension it certainly is not. 4 R.R. Co. v. Jones, 128 Pa. 308. 5 Austin's Jurisprudence (4th ed.),509. 6 Hawkins, Wills, preface; 3 Harv. Law Rev. 141, 148.
