170 HARVARD LAW REVIEW. anything other than mere matters of fact. The circumstance that in order to deal with them it is necessary to know what the legal definition is, does not really affect the matter.^ It is some- times necessary that the jury should be advised as to the ordinary definitions of the dictionaries; but this is needed only to give precision to their inquiry, and does not alter the nature of it. So of any legal definition. The meaning of " burning," in the law relating to arson, is a highly technical one ; and so of " breaking and entering," in burglary; because a definition must be given, is it any the less a simple question of fact whether an accused per- son has burned or broken and entered a given house? And so of such questions as title to property, or insanity. Equally, where the courts or statutes have fixed the legal standard of reasonable conduct, e.g.y as being that of the prudent man, the determination of whether any given behavior conforms to it or not is a mere question of fact^ That in reaching their conclusion the jury must reason, and must "judge the facts," is not material, as we have already seen ; always they must do that ; the difference in this respect between these cases of reasonableness and others is simply one of more or less.^ It is, indeed, to be recognized, as we have seen, that such questions become, from time to time, the subject of more specific legal rule or definition, as in the case of notice of the dishonor of a bill of exchange. But where that has taken place, all that has happened is a change in the legal rules ; the rule of ** reasonableness " is either displaced or narrowed. When once the exacter rule is known, what is left is none the less a mere question of fact. V. As to the other aspect of the maxim, that which excludes the jury from the law, the rule seems to be in a far simpler con- dition. From the beginning, indeed, it was perceived that any general verdict, such as no disseisin, or not guilty, involved a con- clusion of law, and that the jury did, in a sense, in such cases 1 See, for example, People Vi Hawkins, 109 N. Y. p. 411. 2 Eaton V. Southby, Willes, 131 ; Haskins v. Ham. Co., 5 Gray, 432. 8 Vaughan, C. J., in Bushell's Case (Vaughan, p. 142), in speaking of the ordinary sort of question, says : " The Verdict of a Jury and Evidence of a witness are very dif- ferent things in the truth and falsehood of them. A Witness swears but to what . . . hath fallen under his senses. But a Juryman swears to what he can inferr and con- clude from the Testimony of such Witnesses by the act and force of his Understanding to be the Fact inquired after, which differs nothing in the Reason, though much in the Punishment, from what a Judge, out of various Cases considered by him, inferrs to be the Law in the Question before him.**
