#### JAMES K. MELVIN v. HENRY EASLEY.

Professional books, or books of science, (e. g. medical books,) are not admissible in evidence, though experts may be asked their judgment, and the grounds of it, which may in some degree be founded on books, as a part of their general knowledge.

Where counsel, in his address to the jury, read and commented on a book of science, as evidence in the cause, without being interrupted by the adverse counsel, this is no waiver of the error, for it was the duty of the Judge, in his instructions to the jury, to present the case to them properly, and to correct any errors into which counsel may have fallen. '

For the Judge to say that a book on faniery, which had been read by counsel, was entitled to as much authority as a witness, who had been examined (as an expert in the science of diseases of horses,) is a clear violation of the act of 1796, (1 Rev. Stat. ch. 31, sec. 136,) forbidding the Judge to express an opinion on the facts.

This was an action of Assumpsit, for a breach of a warranty of the soundness of a horse, tried before his Honor Judge SauN-DERS, on the last Circuit at New Hanover.

For the purpose of proving the unsonndness of the horse, the plaintiff introduced three witnesses, who testified to the swelling of his sheath, &c., and his death.

The defendant then examined a witness, who stated he had been the keeper of a livery stable, and thought he had some knowledge of the diseases of horses; and upon being asked his opinion, said he thought that the swelling of the sheath was not *387such a disease as would permanently impair the value of the horse, for that it was only a temporary disease.

The counsel for the plaintiff, in his address to the jury, alluded to this testimony of the defendant’s witness, and said that though the swelling of the sheath might not be a disease of itself, it was one of the symptoms of stone in the bladder, which he contended was the disease of which the horse died. In support of this, the counsel referred to a book which he held in his hand, but did not read, which stated this as one of the symptoms of that disease. No objection was taken to this course, and the counsel closed the book, and handed it to the Judge.

His Honor, in his charge to the jury on this point, said that the defendant’s witness had been permitted to express an opinion that swelling of the sheath was not such a disease as to impair, permanently, the value of the horse; and, in answer to this, the plaintiff’s counsel argued, that although this might not be a disease of itself, yet it was one of the external symptoms of stone in the bladder, and referred to the book which he held in his hand, in support of the truth of his position. His Honor then added, that he had looked into the book, and found under the head of “ Stone in the Bladder,” that the swelling of the sheath was stated to be symptomatic of the disease of stone in the bladder; and further, that, as it was an American edition of an English book, that treated of the diseases of horses, he supposed it might be entitled to as much authority in the science as the witness; that, as no post-mortem examination had been made to establish the fact of stone being found in the bladder, it was for the jury to say, under all the circumstances of the case, whether they were satisfied of the unsoundness of the horse at the time of the purchase. Under this charge, the jury returned a verdict for the plaintiff. Whereupon, there was a motion for a new trial, which was overruled, and the defendant appealed.

JJ], Q-. Haywood, for plaintiff.

D. Reid, for defendant.

*388Battle, J.

We have no hesitation in saying that tbe defendant is entitled to a venire de novo, because of two errors committed, to his prejudice, by the Court. The book on the diseases of horses, extracts from which were given in charge to the jury, was not admissible in evidence, and yet the Court gave it all the effect of such. The rule is, that professional books, or books of science, (e. g. medical books,) are not admissible in evidence, though experts may be asked their judgment, and the grounds of it, which may in some degree be founded on books, as a part of their general knowledge. Collier v. Simpson, 5 Carr, and Payne 73, (24 Eng. C. L. Rep. 219,) Cow. and Hill’s notes to Phill. on Ev., pai’t 1, page 761. The reason of the rule is obvious, that if the authors were present, they could not be examined without being sworn and exposed to a cross-examination. Their declarations or statements, whether merely verbal, written or printed and published in books, are not admissible. But it is said that no objection was made when the plaintiff’s counsel referred to and made statements from the book which he held in his hand, but did not read. It was not the duty of the opposite counsel to interrupt the argument of the plaintiff’s counsel, by stopping him to make his objection then, because the presiding Judge was not bound to notice the error at that time. This Court said, in the case of the State v. O’Neal, 7 Ired. Rep. 251, that “ it is the right and the duty of the presiding Judge, if counsel state facts as proved, upon which no evidence has been given, to correct the mistake, and he may do it at the moment, or wait until he charges the jury, perhaps the most appropriate time.” Here the Judge did not correct the mistake at the time, nor when he came to charge the jury. On the contrary, he in effect decided that the book was admissible in evidence, and charged the jury upon it as evidence. In doing this he erred, and then he committed another error, in saying that, “ as it was an American edition of an English book, that treated of the diseases of horses, he supposed it might be entitled to as much authority in the science as the witness.” *389That was a clear violation of the act of 1796, (1 EeV. Stat. ch. 31, sec. 136.) It is the duty of the presiding Judge to decide all questions arising upon the competency of testimony, but he is not at liberty to express any opinion as to its credibility or weight. See State v. Cardwell, Bus. Rep. 245, and the cases therein cited.

The judgment must be reversed, and a venire de novo awarded.