Wood, J.,

(after stating the facts). On examination of the bolt and the model of the machinery about which Hopkins was working when he was killed, we are convinced that the saw kerf in the ragged end of the bolt was made by the front end of the saw, as contended by appellant, and as stated by the witnesses who testified affirmatively to that fact. The kerf shows that it was on a parallel line with the length of the bolt and the marks of the saw teeth as revealed on the inside of the kerf, so far as they are distinctly visible, show conclusively to our minds that it would have been impossible for the kerf to have been made by the. heel of the saw. These saw teeth marks, a few inches on the inside of the saw kerf, indicate unmistakably the direction in which the saw was moving, and they show that the bolt must have approached it from the front end of the saw. If the bolt had approached the heel of the saw, as contended by appellee, the marks of the saw teeth must have been in the opposite direction from what they appear to be. And the kerf, had the bolt approached the heel of the saw, could not have been straight and on a parallel line with the length of the bolt and could not have cut as far into the end of the bolt as the saw kerf shows. Witnesses testify that the bolt would have been thrown up and away from the saw and .that there could not have been force enough to have held it to the heel of the saw, in order to have made the kerf as it appears. Witnesses testify that if the rear dog was released and the rear end of the bolt dropped down and brought back against the saw moving in the direction in which it was going, and with the rapidity it was moving, it would have been impossible to have made the kerf on a line straight or parallel with the length of the bolt. This accords with our view of the physical facts, as shown by the appearance of the kerf in the bolt and the manner of operating the machinery, as testified to by the witnesses and shown by the models as exhibited in the evidence and brought into this record and used in the oral argument.

So, if the liability of the appellant depended upon whether or not the kerf in the bolt was made by the front or the heel of the saw, we would sustain the contention of the appellant on that point, notwithstanding the testimony of the appellee tending to show that the sawyer did not change the ends of the bolt, and notwithstanding the testimony of a witness to the effect that he thought it could have been done in the manner urged by the counsel for the appellee, and notwithstanding the jurors visited the mill plant and viewed the saw slipped into the kerf on the bolt from the heel of the saw. If recovery depended on whether the kerf was made by the front or the heel of the saw, then all of this testimony would come within the rule of Waters-Pierce Oil Company v. Knisel, 79 Ark. 608, and other cases cited and relied on in appellant’s brief. But because tbe kerf was not cut by tbe heel of the saw, it by no means follows that tbe undisputed evidence and tbe physical facts show that Hopkins ’ death was caused in tbe manner contended for by tbe learned counsel of appellant.

Tbe complaint alleges that while tbe bolt was upon tbe carriage tbe sawyer carelessly moved tbe lever, so as to cause tbe carriage to run backward and thereby brought tbe bolt again in contact with tbe saw, which was running at a great speed, and threw same with great force against appellee’s intestate.

Tbe evidence is set forth somewhat at length in tbe statement and there is some testimony to warrant tbe jury in finding that tbe death of Hopkins was caused in the manner alleged in tbe complaint. It was shown that there was a defect in tbe lever of tbe carriage and that unless tbe sawyer was careful in handling it, tbe carriage would run away. There is no dispute that Hopkins was killed by tbe bolt striking him on tbe head. There was testimony to warrant tbe jury in finding that tbe bolt passed through tbe saw. One witness testified positively to this effect. It was within tbe province of tbe jury to believe this testimony, although tbe decided preponderance of tbe evidence may show to tbe contrary. If tbe bolt passed tbe beel of tbe saw, tbe only possible way in which tbe death of Hopkins could have resulted under tbe evidence, was as alleged in tbe complaint. That it did so result is not contrary to tbe physical facts. Although tbe kerf in tbe bolt was made by tbe front of tbe saw, and although tbe sawryer after this changed tbe ends of tbe bolt and passed tbe bolt through tbe saw with tbe smooth end in front, still if be carelessly caused tbe carriage to move back, after tbe block bad passed through, but before it was entirely released from tbe dogs, causing tbe rear end of tbe bolt to move toward tbe saw, tbe bolt might have been caught by tbe saw teeth in tbe edge of tbe kerf and in tbe splintered and jagged end thereof and been burled against Hopkins.

On examination, after sawing off tbe end of tbe block and exposing the inside of the kerf to view, the jury might have come to the conclusion that the saw teeth caught between the edges of the kerf at the splintered and ragged end of the block and were thereby fastened long enough to throw the block over against Hopkins. While the upper end of the kerf is comparatively smooth and shows plainly the saw teeth and the direction in which the saw was moving when the imprint of the saw teeth was made, the lower end of the kerf or that next to the carriage, was more or less frazzled, with the fibers of the wood broken down on the inside of the kerf, and there are indentations or marks on the inside of this kerf, indicating where the saw teeth had been and showing by the splintered condition of the sides of the kerf, that the saw teeth might have fastened in the wood. After sawing off the piece of the end showing the inside of the kerf, the jury concluded that the testimony showing that the bolt passed the heel of the saw, was true and that the carriage was moved back by the sawyer and the bolt thus brought in contact with the heel of the saw, fastening the teeth of same in the kerf of the ragged end of the bolt and hurling it over against Hopkins, according to the theory of the appellee. We are of the opinion that this explanation and theory as to how the injury was produced, is not contrary to the physical facts. The witness who testified that the bolt went past the saw also testified that he saw the off-bearer reach for it but did not know whether he took hold of it or not. This testimony was believed by the jury and it tended to show that the bolt did pass the end of the saw, for it would be unreasonable to conclude that the off-bearer would reach for the bolt before the same had passed the saw. Especially would it be foolhardy for him to have exposed himself to the danger of doing so, if the front end of the bolt was still some eight inches from the rear end of the saw, as one of the witnesses for the appellant testified it was.

The theory of appellant was, that after the saw passed through the bolt, but before the front end of it reached the rear end of the saw, Hopkins released the dog without moving the bolt back from the saw by the use of the ratchet wheel, and that the saw thus came in contact with the bolt, and the friction thereby created threw the bolt over against Hopkins. But the testimony of the witness on behalf of the appellee, showing that the entire bolt passed through the saw and that the rear end of the bolt passed the heel of the saw, and tending to show that' the off-bearer reached for the bolt, is in direct conflict with appellant’s theory and contention.

It was wholly within the province of the jury to believe and accept the testimony of the witness for the appellee and to disbelieve and reject the testimony of the witnesses for the appellant, and we will not disturb their verdict, although it may seem to us to be contrary to the decided preponderance of the evidence. See St. Louis & S. F. Rd. Co. v. Kilpatrick, 67 Ark. 47.

Second. The appellant objected to the testimony of certain wetnesses on the ground that it was opinion evidence and that the testimony was not competent. Several of the witnesses for the appellant had testified that the sawyer changed the ends of the bolt, which injured the appellee’s intestate. One witness on behalf of appellee was permitted to testify, over the objection of appellant, that he had never changed the ends of a bolt. Witnesses further testified on behalf of the appellee to the effect that they had examined the bolt and that the imprint of the dog teeth on the plain or square end of the bolt looked to be the same, and there were other expressions of opinion of certain witnesses on some phases of the case to which objection was made. We have examined these and are of the opinion that there was no prejudicial error in the ruling of the court in permitting this testimony and in not excluding the same from the jury. It was shown from the length of time the witnesses had been employed by mill plants of the kind under consideration and their familiarity with such machinery, that they were experts. Their opinion related to the subject-matter with which the jury were not supposed to be so familiar as they. The testimony, therefore, was competent. Dardanelle, P. B. & T. Co. v. Croom, 95 Ark. 284-290. See also Kansas City So. Ry. Co. v. Henrie, 87 Ark. 443; St. Louis, I. M. & S. Ry. Co. v. Dawson, 77 Ark. 434.

Third. The court did not err in refusing to modify instruction No. 7. That instruction was but a continuation of instruction No. 6, which was as follows:

“If you find from the preponderance of the evidence that Sullivan, the sawyer, at the carriage where deceased worked, was negligent, as that term has been defined, in the performance of any duty which he owed to deceased, and that the injuries sustained by deceased resulted from such negligence on the part of Sullivan, and that at the time of being injured, deceased was in the exercise of due care for his own safety, your verdict will be for the plaintiff. ’ ’

The court had also used the term in the first instruction in connection with the duty of the deceased, to exercise “due care” for his own safety. The effect of'instruction No. 6 was to tell the jury that, even though the sawyer was negligent and that such negligence resulted in the death of Hopkins, still appellee could not recover unless Hopkins was in the exercise of “due care” for bis own safety. Having used the term “due care” in connection with the duties of Hopkins in the sixth instruction, the court in its instruction No. 7 was simply defining what the term “due care” meant, so that the jury might have a proper conception of what was required of Hopkins, as a condition precedent to the recovery by the appellee. The term was not used in defining the duty of the sawyer, the employee of appellant, whose negligence was alleged to have been the cause of the injury. The court had correctly defined “negligence” in other instructions. It will therefore be seen at a glance that the modification was not at all germane to the subject-matter of the instruction which the appellant requested to be modified. As a modification to instruction No. 7 it was entirely a misfit and the court did not err in refusing it because of that fact.

A modification to an instruction should pertain to the subject-matter which the instruction itself contains. If the appellant desired such an instruction . it should have presented it as a separate and independent prayer or in connection with some prayer in which the court was defining the duty of the employee, whose negligence was alleged to have caused the injury complained of. But the requested modification, even if presented as an independent prayer for instruction, was not the law and therefore the court did not err in refusing it. It was not necessary in order to make the company liable that Sullivan, the sawyer, should actually know that his fellow-servant, Hopkins, was in danger. It was sufficient, if the sawyer, in the exercise of ordinary care in the performance of his duties as an employee, could or should have known that his act in reversing the carriage might result in the injury to his fellow-servant. A corpora-. tion can only act through its servants and agents, and those through whom it acts must exercise ordinary care in the discharge of their duties, to avoid an injury to fellow-servants, that by the exercise of such care, could and should have been reasonably anticipated and avoided. The. effect of the requested modification was to tell the jury that appellant was not liable unless Sullivan had discovered the peril of Hopkins before running the saw carriage containing the bolt back to the saw. If this were the law, the master would not be liable for an injury to his servant unless such injury was caused by the wilful or gross negligence of the employee causing the injury. Sullivan being in control of the movements of the carriage and knowing the positions of the respective fellow-employees working with him and the consequences likely to result to them from his failure to exercise ordinary care in the performance of his own duties, would render his master liable for an injury resulting to a fellow-employee by reason of such failure. Act 69, Acts of Ark. 1907, p. 163; see Aluminum Co. v. Ramsey, 89 Ark. 522.

Fourth. The record presents no question for review concerning the alleged improper remarks of counsel. If the remarks of counsel were improper, they were not, to say the least, so flagrant as to be prejudicial at all events. While it is the duty of the court on its own motion to make such rulings as may be necessary to correct the prejudicial effect df any improper argument (Vaughn v. State, 58 Ark. 353), it is also the duty of the party affected by any improper argument to except to the failure of the court to take the necessary steps to remove any prejudicial effect of such argument. Unless the party affected excepts to the failure on the part of the court to remove, or to attempt to remove, the prejudice of the improper argument, he will be deemed to have waived any error predicated thereon. Meisenheimer v. State, 73 Ark. 407; Southwestern Tel. & Tel. Co. v. Abeles, 94 Ark. 254.

Affirmed.

Smith, J., disqualified and not participating.