This is an appeal from a judgment respondent recovered for damages for injuries she received from falling when she attempted to pass from her seat into the aisle of a moving-picture theater owned and operated by appellants. The evidence conflicts. That for respondent tends to show the theater was quite dark; she was unable to see the floor at her feet; she could see, merely as a dark object, her companion who preceded her into the aisle; she left *276her seat and walked toward the aisle; as she did so she held to the back row of seats in front of her; the seats were upon a platform or floor which at the end of the row in which respondent had been seated was four inches above the level of the aisle; as respondent attempted .to enter the aisle her heel was caught or placed upon the edge of the floor upon which the seats stood and she lost her balance and fell; she was seriously injured. She had not previously visited the theater. There is no dispute that patrons were invited to enter and leave, and did enter and leave, the theater at will during performances.
Numerous errors are assigned. Other facts can best be stated in connection with the particular questions to which they are relevant.
NegUgence. I. It was the duty of appellants to use ordinary care to see that the place to which they invited their patrons was reasonably safe for use for the purposes for which it was designed. [Hollis v. Merchants Assn., 205 Mo. 1. c. 520.] The jury was warranted in finding that respondent’s fall was due to her inability to see the step-off on account of the darkness in the theater. “It is a matter of common knowledge” that a four-inch depression in a floor “is sufficient to cause one to fall” who, in the absence of light and knowledge of its presence, steps into or upon the edge of it. [New Theater Co. v. Hartlove, 123 Md. 1. c. 86.] It is not contended the presence of the step-off, alone,, was negligence. It was the absence of light sufficient to enable respondent to see the depression which brought "about her fall. The evidence was. sufficient to warrant a finding of negligence. [Valentine Co. v. Sloan, 53 Ind. App. 71; New Theater Co. v. Hartlove, 123 Md., supra; Andre v. Mertens, 88 N. J. L. 628; Marwedel v. Cook, 154 Mass. 235; Little v. Holyoke, 177 Mass. 116; Faxon v. Butler, 206 Mass. 504; Marston v. Reynolds, 211 Mass. 592; Nephler v. Woodward, 200 Mo. 179; Camp v. Wood, 76 N. Y. 95; Currier v. Music Hall, 135 Mass. 414.] Appellants *277rely upon eases holding that steps and stairways of ordinary construction are reasonably safe when used as means of overcoming differences in level. They do not decide the question in this case. [Little v. Holyoke, 177 Mass. 116.] Peck v. Yale Ainusement Co., 195 S. W. 1033, is cited. In that case the evidence failed to show what caused the injury. Mrs. Peck was familiar with the stairway,' and the light was like that usually found in moving-picture theaters. In attempting to use a properly constructed stairway of the presence of which she had previous knowledge, she fell, and from her evidence “no court could say just what did cause her fall.” That case is not in point. The question of negligence in this case was for the jury.
Negligence!7 II. The question of contributory negligence was for the jury. The passage between the seats led into the aisle as a means of egress. Seeing others use the aisle and invited to use it herself, “can. ^ sa^) as a matter of law, that a person seeking to leave a public theater, and following the only path leading to an exit, should apprehend that that path contained an unsafe place or pitfall or the like?” [Branch v. Klatt, 165 Mich. 671.] In the same case it is said that “the very fact of the premises being maintained in a darkened condition might give added assurance of its being reasonably safe.” The evidence fairly supports a finding against contributory negligence. [New Theater Co. v. Hartlove, supra; Andre v. Mertens, supra; Nephler v. Woodward, 200 Mo. 188; Lewis v. Shows Co., 98 Kan. 118; Marston v. Reynolds, supra; Faxon v. Butler, supra; Marwedel v. Cook, supra.]
pSitionng III. The petition originally counted on (1) common-law negligence, and (2) violation of Section 156 of the Building Code. The answers pleaded at length Ordinance No. 7667, which purports specifically to regulate, in some respects, moving-picture shows. It contains this provision: “No steps shall be permitted in any aisle or in any part *278of the auditorium floor, except by written permission of the Superintendent of Buildings and Fire Warden.” The answers averred this - ordinance repealed Section 156 of the Building Code insofar as it applied to moving-picture shows. They also 'averred the building was inspected and approved by the Superintendent of Buildings and- Fire Warden, and, subsequently, a license to conduct the show was issued. Appellants offered evidence tending to show the plans for remodeling were approved by the Superintendent of Buildings, and that the Fire Warden inspected the premises after the work was completed.- No formal -written permission to install the step-off was in evidence, and no writing of any kind, signed by the Fire Warden, was offered. Appellant owners testified they knew of no other permits having been issued. After the evidence was in, respondent secured leave to amend her petition by interlineation to conform to the proof by adding a charge that Ordinance 7667 had been violated.
The amendment to the pleading did not change the defense. Appellants’ answers had been on file nearly six months. Those answers pleaded Ordinance 7667 in full, and pleaded inspection and approval thereunder by the Superintendent of Buildings and Fire Warden, and the subsequent licensing of the theater as a defense to the action. Compliance was essential to such defense. Counsel contended then and contend now that their evidence showed, as a matter of law, that appellants had complied with the provision requiring written permission for the installation of the step-off. Every official who acted in the premises was put on the stand. Proof was made by appellants that every writing issued by the officials was in evidence. The issue was fully tried. There was a total failure of written permission by the Fire Warden. Indeed, the proof was he had given no. such permission. This proof was made by appellants. One charge in the petition was that a provision of a designated ordinance prohibited inequalities in floor levels. Ordinance 7667 contained a like prohibition, subject to exception on *279written permission of named officials. The substance of the charge in the original petition was a violation of an ordinance prohibition against inequalities. The substance of the amendment was a like charge. The differences lay in the number of the ordinance. That ordinance was pleaded by appellants, and the issue respecting compliance with it was tried at length. In such circumstances the allowance of the amendment was right. [Sec. 1848, R. S. 1909; Wright v. Groom, 246 Mo. 163 et seq.; Sonnenfeld v. Rosenthal, 247 Mo. 266, et seq.]
. . Permission. IV. It is urged permission under Ordinance 7667 was shown. ‘No pretense is made that any formal permission in writing was given by any official, and it is clear no written permission of any kind wag g^ven py Fire Warden. Appellants proved the contrary. General definitions of “permission” are of little value. The language of the ordinance is unambiguous. There is no room for a construction that the ordinance could .be satisfied by implying permission from inspection of the premises. Appellants had the benefit of an instruction directing a verdict for them if the step-off was no higher than the approved plans indicated.
ordinance, V, It is contended Ordinance 7667 is void because of the provision forbidding the employment of’ steps “except upon the written permission” of certain officials. It is said this vests an arbitrary power in the officials and falls within the principle applied in Hays v. Poplar Bluff, 263 Mo. 516, and like cases.
An ordinance conditionally restricting the exercise of a right, otherwise exercisable without question, and making that exercise dependent upon the arbitrary will of a city officer, may well be held invalid. On the other hand, matters of • detail in enforcing ordinances otherwise valid may be left to designated officials. Again, it is held quite generally that in case *280the city may prohibit a particular thing, it validly may prohibit it except in case a permit is procured from désignated officials. [City of St. Louis v. Fischer, 167 Mo. 662, et seq.; affirmed, Fischer v. St. Louis, 194 U. S. 371.] The arbitrary exercise of the discretion would present another question. In this case it is not suggested the city might not lawfully prohibit absolutely inequalities in levels in darkened theaters. It might do so. The case falls within the rule in the cases above cited. [2 Dillon on Municipal Corporations, sec. 598.] The cases cited by appellants fall within the other principle.
Demurrer. VI. The demurrer appellants asked leave to- file was general in character except insofar as it questioned the validity of Ordinance 7667. That ordinance was valid. The petition was not vulnerable to this gorj. a^aejc< j-fc jg not now denied, as we understand it, that it states a cause of action. The filing of the demurrer could have availed appellants nothing.
to°Eiect VII. After the amendment to the petition, appellants asked leave to file a motion to require respondent to elect between the section of the building code pleaded and Ordinance 7667. Respondent immediately announced she elected to stand upon the common-law7 allegation and Ordinance 7667. She thereupon requested instructions, which were given, withdrawing from the jury the section of the building code and directing them to- disregard it. No formal filing of a motion to elect could have secured appellants more.
of Risks.1011 VIII. The trial court was right in refusing the instruction on the assumption of risk. The instruction ignored the question whether there had been a violation of the ordinance pleaded. It also ignored the fixation whether the usual construction and lighting of theaters in Kansas City was negligent. Other instructions refused commented on *281the evidence or ignored substantial questions or contained improper assumptions. Twenty instructions were given for appellants. These presented their case in a favorable light.
(mi «Thom Instruction 2% given' for respondent told the jury, in substance, that if appellants permitted a step in thq floor without the permission required by Ordinance 7667, the fact that other theater owners per- * ~~ mitted similiar steps constituted no defense. Courts do not permit the defense of custom to be made to violations of positive law. Further,. the evidence' showed no customary construction like that appellants insist was harmless. There was evidence that about one out of ten theaters in Kansas City had steps in the floor. The objections made to this instruction are not tenable.
Juror IX. There was no error in sustaining the challenge to the talesman Caldwell. He testified his business relations with appellants were such that they might a®ec^ his verdict; that' he preferred not to sit; that he felt “embarrassed .to sit as a juror against these two men.” He further stated he would exercise his judgment in returning- a verdict according to the law and the evidence; that- he would endeavor to do his duty. There is no ground for saying, in these circumstances, that the trial court acted arbitrarily in rejecting Caldwell. He heard Caldwell’s testimony, observed his demeanor and was in a better position to pass upon the question the challenge presented. We are cited to no case which, in a like situation, holds a like ruling reversible error'.
Testimony. X. It is argued that it was error to permit an expert to testify that it was practicable to overcome differences in floor levels in theaters' by gradients or inclined planes. It is said the jury was as a^e to draw conclusions upon this question as was the expert. All will agree differences in levels can be overcome in the manner stated. *282Whether such methods of overcoming ■ them in theater floors are practicable is another question. The evidence falls within the rule in Combs v. Construction Co., 205 Mo. 391, and was admissible.
Affirmed.
All of the judges concur; Bond, P. J., in result.