Again, in the case of Nashville & Chattanooga Railway vs. J. N. Carroll, 43 Tenn., 368, it was urged that the court erred in refusing to allow an expert to testify what was meant by an obstruction. It was a railroad accident case, and one of the allegations was that the railroad had permitted an obstruction to remain upon the tracks, thus causing the wreck. The obstruction being a hand-car, I believe. The court held that there was no error in excluding the evidence of an expert as to what constituted an obstruction saying: "What is or is not an obstruction, is a simple question of fact which could be determined by the jury as well as the expert."
Now, what are the issues in this case, if the court please? The indictment simply charges that John Scopes taught, in violation of law, that man has descended from a lower order of animals, and the state has offered evidence tending to prove that he did so teach. As a matter of fact, this evidence has not been controverted by the defendant. There is no issue of fact raised by evidence, the facts are agreed upon both sides. Under this state of evidence, if the court please, if this were a civil case instead of a criminal case, your honor would he compelled to take the case from the jury and find for the plaintiff. What issue of fact is there left for the experts to express an opinion upon? There is no issue of fact upon which expert testimony is either proper or necessary. The only question in this case is, whether or not the jury believes that the admitted facts show a violation of the law, and this, I submit, is one of those mixed questions of law and fact to be determined by the jury under the proper instruction of the court, and can never be a proper subject of expert testimony.
And now, if the court please, I come to the limitation I adverted to a moment ago; and that is, that opinion evidence may not, under any circumstances be received to determine the fact in issue; in other words, to invade the province of the jury. The rule is stated in 22 Corpus Juris, 502, and the hundreds of citations supporting it as follows:
"As the opinion evidence rule against admissability is to provide against the mischief of the invasion of the province of the jury, a court should exclude the inference, conclusion or judgment of a witness as to the ultimate fact in issue, and this is true, even though the circumstances presented are such as might warrant a relaxation of excluding the opinion, but for this one circumstance."
In other words, it matters not how technical the subject, how involved the issue may be, there is one place where expert testimony may never, in any event, be received; and that is where it is upon the very issue that the jury is to determine, and that is the situation in this case, if the court please. This has always been the law in Tennessee, as well as other states.
The Court—What case do you read from?
Mr. Bryan—I will read from the case of Bruce vs. Beall, 99 Tennessee, 313. This was, if I remember rightly, a case for personal injuries received in the fall of an elevator, and one of the questions at issue was whether the defendant had been negligent in permitting the cables to be used for a certain period of time, and the court excluded certain questions asked the expert as to whether or not the use for that length of time was safe or not. The court used this language:
"While the general rule is that witnesses must speak the facts, yet, upon questions of skill and science, experts are competent to give their opinions in evidence, but they will not be permitted to state their opinion upon any point the jury has to decide. Deductions from facts belong to the jury, and when the examination extends so far as to substitute the opinion of the witness upon the very issue in controversy, for that of the jury, the province of that tribunal is unwarrantedly invaded. We think it is clear that in no case can the witness be allowed to give
