Ladd, C. J.
The plaintiff, while working as a section hand on defendant’s line of road, Saturday, October 28, 1899, stepped aside to allow a freight train to pass. It was moving up grade, to the southwest. He stood to the southeast, about twelve feet from the track, looking in the same direction, and the wind was blowing from the northwest. When the engine had passed about one hundred, feet, something struck him in the eye, causing a burning-sensation and pain. One Erederickson shortly after removed two substances. “The first seemed to be a wooden, fibrous matter, and the other a small coal cinder, * * % about the size of an-ordinary pin head. ” Later in the day the eye was examined by a physician, who took out a. similar particle. On Monday following, a specialist removed a particle of coal, or like substance, “as large as. the liead of an ordinary, brass pin,” which was deeply imbedded in the cornea. The outcome of it was the loss, of sight in that eye.
1 i sparks geuce' Upon proof of these facts, the jury, by direction of the court, returned a verdict for the defendant. Exception is taken to this ruling, but we think it correct. Though much to be regretted, human ingenuity has not yet been able to produce a devise or apparatus wholly adequate to prevent the¡ *642emission of sparks and cinders from a locomotive engine when moving a train of cars at the customary rate of speed. The necessity of a draft of air to keep up the fire is such as to render it impractical to reduce the openings in the spark arrester to a size so small as to prevent the escape of particles. This is generally understood, and possibly courts should take judicial notice of the fact, as a matter of common knowledge. Menomonie River Sash & Door Co. v. Milwaukee & N. R. Co. (Wis.) 65 N. W. Rep. 176. At any rate, the emission of particles of coal or sparks, not unusual in size or quantity, will not, alone, warrant the inference of negligence, either in the improper management of the engine, or its lack of equipment with appliances of approved efficiency. Savannah, F. & W. R. Co. v. Tedman (Fla.) 22 South. Rep. 658; Gandy v. Railroad Co., 30 Iowa, 420; McCummons v. Railway Co., 33 Iowa, 187; Garrett v. Railway Co., 36 Iowa, 121.
*6432. same: as-of risk.011 *642If it could be said that the injury to plaintiff’s eye “was occasioned by fire set out or caused by operation of such railway,” — which hardly seems possible, — such injury is not within the purview of the section of the statute casting the burden of proof in such cases on the defendant. Section 2056, Code. The damages there contemplated are those “sustained by any person on account of loss or injury to his property.” The words quoted were inserted in that portion of section 1289 of the Code of 1873 relating to damages occasioned by fire set out or caused by the operation of a railway, and, thus changed, enacted as section 2056 of the Code. The modification was evidently made to meet the decision in Liming v. Railroad Co., 81 Iowa, 246, awarding damages occasioned by injuries to the person. No evidence of any défect in the construction or operation of the engine was introduced, or that smoke ,or cinders and sparks of unusual size or quantity were being thrown out. The specks taken from the eye did not *643appear to be larger than a pin head, and it cannot be inferred that, because of emitting them, the defendant was negligent. See. Weidmar v. Railroad Co., 114 N. Y. 462 (21 N. E. Rep. 1041); Searles v. Railway Co., 101 N. Y. 661 (5 N. E. Rep. 66). The hazards incident to the ordinary perils of his employment were assumed by the plaintiff. He must necessarily step aside from his work on the tra'ck in order that trains may pass. Sparks and cinders were likely to be thrown out of the engine at any time when in operation. This he was bound to know, and, if injured thereby without negligence on the part of defendant, he cannot recover.
„ eípeUrSt10tes-f: timony. II. ■ Appellant, when on the witness stand, was asked whether he noticed that there was a great amount of smoke coming from the engine. An objection was sustained. As he stated afterwards .that he did not know, the ruling was without prejudice. Again, objection was. sustained to the question “whether it apparently came from the engine, or in the direction from the engine.” To what “it” referred, is not disclosed in the record. Assuming that smoke, wind, or the cinder was the antecedent, the ruling, in view of what has already been said, could not have affected the conclusion. The court refused to allow the specialist to say whether he could have told, had the cinder been larger, if it was hot when it struck the eye. Such evidence would have been entirely irrelevant. Expert opinion is necessarily confined to the facts as developed on the trial. As the physician said that he could not tell in this particular case, there was no error in not allowing him to answer subsequently whether he could tell with the facts as they in fact were. .
*6444. taxation nessfees. *643III. Six persons attended court at defendant’s request for the purpose of giving their testimony when called. Fees for attendance and mileage in their behalf were taxed as part of the costs by the clerk. Upon *644discovery that they had not been subpoenaed, the plaintiff, as they had not been used, moved a retaxation, eliminating any allowance to them. In resistance, the defendant made a conclusive showing that, had not the case been taken from the jury, these persons would have been used as witnesses, and given testimony material to the issues, and that they were in attendance for this purpose only. No showing was made of the distance traveled by each. The court held that 'fees for attendance had been properly taxed, but that mileage should not have been allowed. From this ruling the defendant appealed. It was clearly correct. As they had not been summoned in the usual way, and the record failed to show that they had been called as witnesses, the burden was upon the defendant to vindicate the propriety of taxing the costs. This it entirely omitted in the matter of mileage. But the showing was sufficient as to attendance. The service of a subpoena is in the interest of the party desiring the attendance o'f the witness, and not of his opponent. If he will attend voluntarily, such service would be superfluous and of benefit to neither party. The omission to swell the costs with the additional expense in officer’s fees and mileage for issuing and serving subpoenas furnishes no ground of complaint by the other side. . It is rather a favor, in the way of eliminating unnecessary expenses. Christensen, v. Union Trunk Line (Wash.) 32 Pac. Rep. 1018; Farmer v. Storer, 11 Pick. 241; U. S. v. Sanborn, 28 Fed. 299; Crawford v. Abraham, 2 Or. 166. The plaintiff relies on Fisher v. Railroad Co., 104 Iowa, 588. Butin that case no showing whatever was made. So far as appeared, the persons whose fees were involved may have no knowledge or connection with the case whatever. See Briggs v. Rumely, 96 Iowa, 202. — Aeetrmed.