delivered the opinion of the court.

This case was heretofore before us and is reported in 59 Miss. 594. Two juries have, by their verdicts, declared that the will of P. W. Tucker was mutilated after his death by the hand of a spoliator, and we must accept their finding as conclusive, supported as it is by testimony which seems to have warranted it. Two alleged errors of law only are seriously pressed upon our attention.

Brabson, a witness for the contestants, having testified to important facts on their behalf, was, upon cross-examination, questioned as to certain statements alleged to have been made by him upon an immaterial matter only remotely connected *469with the issue. When the question was propounded it was objected to.; but the objection being overruled, the witness answered that he had not made, the statement attributed to him in tbe interrogatory. Subsequently two witnesses, introduced by the proponent for the purpose of contradictiug him, testified that he had made the statement to them. To the introduction of the testimony of these witnesses no objection was interposed. The action of the court under these circumstances was not erroneous. It is generally admissible, and often advantageous, to cross-examine upon collateral or even immaterial matters, and the refusal of the court to sustain the objection as to this was correct^

Contestant’s objection was not directed to the right point. While it was entirely proper to cross-examine on the immaterial matter, it was not allowable to impeach the witness as to that matter. But to the impeaching testimony there was no objection, and the court having ruled correctly on the only objection made was not bound to extend it to a point where it would have been applicable and interpose it of its own motion.

There being in the case some question as to the effect of paralysis on the human arm (the investigation being calculated, as was thought, to throw some light on the inquiry whether the deceased, who was paralyzed, had or had not torn his own will), the contestants introduced a physician to testify as an •expert on this subject, and while he was on the stand offered in evidence a copy of Copeland’s Medical Dictionary, and proposing to prove its high character in the medical profession, ■offered to .read some extracts from it to the jury, counsel stating (as the bill of exception recites) “that the extracts referred to paralysis of the arm, with a view of allowing said extracts to be read to the jury.”

We cannot regard this, under the statement of the bill of •exceptions, as a proposition that the expert should read the book as corroborative or explanatory of his own testimony, nor as a request that counsel should be permitted to make it a part of their argument. As to the admissibility of a book of *470science for either of these purposes the authorities are divided, it not unfrequently being held to be a matter resting in the sound discretion of the court. The proposition here, as we understand it, was to introduce the extracts as primary evidence before the jury, and viewed in this light, it was clearly inadmissible, as held by the great weight of authority. Extracts from such a book could be no more than a written statement of the opinion of the author, expressed perhaps many years before, liable to subsequent change or modification, not delivered under oath or in the presence of the court, with no opportunity for cross-examination by the other side, nor of explanation and application to the particular facts of the case in hand by the author. However high, therefore, may be the general character of the work, it lacks every safeguard which distinguishes hearsay from legal evidence, and stands, therefore, upon a far inferior and wholly different footing from the testimony of the humblest expert.

There is a class of books which are admitted before the jury as primary evidence; but these are such as relate to sciences deemed exact, or such as by long use in the practical affairs of life have come to be accepted -as standard and unvarying authority in determining the action of those who used them.

To the first-class belong almanacs, astronomical calculations, tables of logarithms and the like, to the second tables of life expectations in matters of insurance. The following, among other authorities, hold the rule announced by us as to the inadmissibility of the preferred evidence in this case : 2 Beck’s Med. Jur. 963, et seq.; 1 Greenl. on Ev., sect. 440, and note; 1 Whart. on Ev., sects. 665-666 ; 5 Car. & P. 74; 1 Gray, 337; 8 Gray, 431; 117 Mass. 139.

Affirmed.