The English and American authorities agree that medical, or other scientific books, are not competent evidence in courts of law; they cannot be put in evidence, although the medical witnesses state that such books are works of authority in medicine. Tindal, C.J., thought that witnesses might be asked whether in the course of their reading they had found such-and-such a rule laid down; they might be asked how far their opinion was founded on books, and might refer to such books; they might be asked their judgment on the point, and the grounds of it, which may be in some degree founded on these books, as a part of their general knowledge, but the book itself could not be read. And as late as 1875, Mr. Justice Brett refused to allow Taylor’s Medical Jurisprudence to be read to the jury, saying: “That is no evidence in a court of justice. It is a mere statement by a medical man of hearsay facts of cases at which he was, in all probability, not present. I cannot allow it to be read.” And the refusal seems to be the rule in England. And Redfield, C.J., says, that when objected to, these books have not generally been allowed to be read in the United States, either to the Court or jury. And a very recent writer says, “The result of the cases on this subject shews clearly that the very decided weight of authority is against the admissibility in evidence of standard medical treatises.” Such is the rule in England, Ontario, Indiana, Maine, Maryland, Massachusetts, Michigan, North Carolina, Rhode Island and Wisconsin, supported by _dicta_ in California and New Hampshire, and opposed by decisions in Alabama and Iowa [246]. |100| In Iowa and Wisconsin such books have been allowed to be read, the Court in one case remarking, “The opinion of an author, as contained in his works, we regard as better evidence than the mere statement of those opinions by a witness, who testifies as to his recollection of them from former reading. Is not the latter secondary to the former? On the whole, we think it the safest rule to admit standard medical books as evidence of their opinions upon questions of medical skill or practice involved in the treatment.” In Wisconsin, however, the court seems now to have overruled its earlier decisions, and to have sided with the majority [247].