We give first consideration to the sixth and fifteenth exceptions, which are based on the refusal of the trial court to dismiss the action upon a compulsory nonsuit under the statute. G.S. 1-183.
The driver of a motor vehicle is not an insurer of the safety of a person riding therein as an invited guest. But he is required by law to exercise reasonable care to protect such person from harm. Accordingly, he is liable for an injury to a guest proximately resulting from his negligence in the operation of the automobile. Wright v. Wright, 229 N.C. 503, 50 S.E. 2d 540; Henderson v. Powell, 221 N.C. 239, 19 S.E. 2d 876; *284 Montgomery v. Blades, 218 N.C. 680, 12 S.E. 2d 217; White v. McCabe, 208 N.C. 301, 180 S.E. 704; Ballinger v. Thomas, 195 N.C. 517, 142 S.E. 761. When the evidence presented by the plaintiff at the trial and this rule of law are laid side by side, it is manifest that such evidence was sufficient to establish actionable negligence on the part of the defendant. It tended to show that the plaintiff suffered personal injury as the proximate consequence of the negligent failure of the defendant to ascertain whether he was in a position of safety before she put her car in motion. Hernandez v. Murphy, 46 Cal. App. 2d 201, 115 P. 2d 565; Moore v. Davis (La. App.), 199 So. 205; Corrigan v. Clark, 93 N.H. 137, 36 A. 2d 631.
Moreover, it cannot be said that the plaintiff was contributorily negligent as a matter of law in that he attempted to hoard the automobile of the defendant or to seat himself therein in a dangerous fashion. Under the testimony opposing inferences were permissible on this particular aspect of the ease, and it was, therefore, a question of fact for the jury whether the plaintiff was guilty of contributory negligence. Groome v. Davis, 215 N.C. 510, 2 S.E. 2d 771; King v. Pope, 202 N.C. 554, 163 S.E. 447.
Furthermore, the record does not justify the conclusion that the proof presented by the plaintiff established a cause of action different from that alleged by him. Even if it be taken for granted that the evidence offered did not correspond in all respects with the allegations of the complaint, the resultant variance must be adjudged immaterial; for nothing in the record suggests that it actually misled the defendant to her prejudice in maintaining her defense upon the merits. G.S. 1-168; Simmons v. Lumber Co., 174 N.C. 220, 93 S.E. 736; Mode v. Penland, 93 N.C. 292.
These things being true, the trial court rightly refused to nonsuit the action.
Certain assignments of error are addressed to the admission of testimony given by the plaintiff’s physician, Dr. Willard Cardwell, a conceded medical expert. It is well settled in the law of evidence that a physician or surgeon may express his opinion as to the cause of the physical condition of a person if his opinion is based either upon facts within his personal knowledge, or upon an assumed state of facts supported by evidence and recited in a hypothetical question. Patrick v. Treadwell, 222 N.C. 1, 21 S.E. 2d 818; Yates v. Chair Co., 211 N.C. 200, 189 S.E. 500; Godfrey v. Power Co., 190 N.C. 24, 128 S.E. 485; Martin v. Hanes Co., 189 N.C. 644, 127 S.E. 688; Brewer v. Ring, 177 N.C. 476; 99 S.E. 358; Taylor v. Power Co., 174 N.C. 583, 94 S.E. 432; Ridge v. R. R., 167 N.C. 510, 83 S.E. 762, L.R.A. 1917E, 215; Lynch v. Manufacturing Co., 167 N.C. 98, 82 S.E. 6; Holder v. Lumber Co., 161 N.C. 177, 76 S.E. 485; Pigford v. R. R., 160 N.C. 93, 75 S.E. 860, 44 L.R.A. (N.S.) *285865; Beard v. Railroad, 143 N.C. 136, 55 S.E. 505; Summerlin v. Railroad Co., 133 N.C. 550, 45 S.E. 898. As we interpret the record, the third, fourth and fifth exceptions related to the hypothetical question asked Dr. Cardwell by counsel for plaintiff. This hypothetical question was framed properly, and merely elicited from the physician his opinion as to the cause of the suffering alleged to have been endured by the plaintiff. Hence, these exceptions are without validity. The defendant maintains with some plausibility that the trial court erred in receiving the portion of Dr. Cardwell’s testimony, which is the subject of the first and second exceptions. Bo this as it may, these exceptions are not subject to review in this court for the same witness gave substantially the same testimony without objection in other portions of his examination. Indemnity Co. v. Perry, 200 N.C. 765, 158 S.E. 560; Smathers v. Jennings, 170 N.C. 601, 87 S.E. 534; 5 C.J.S., Appeal and Error, section 1735.
The seventh, eighth and eleventh exceptions challenge rulings excluding testimony of the defendant’s medical witness, Dr. A. J. Tannenbaum, that he had examined a skiagraph which he assumed to be an X-ray photograph of the plaintiff’s skull, and that such picture disclosed “no -objective evidence of bony disorder.” Expert evidence as to what a duly authenticated X-ray picture shows is undoubtedly admissible where it tends to aid the jury to understand the nature and extent of injuries involved in the action on trial. Eaker v. International Shoe Co., 199 N.C. 379, 154 S.E. 667. The trial court rightly rejected Dr. Tannen-baum’s interpretation of the skiagraph in question, however, for it did not appear by competent evidence that such X-ray photograph was actually a picture of the plaintiff’s skull. These observations of a text writer seem pertinent here: “An X-ray picture cannot be authenticated in the same manner as an ordinary photograph, that is, by testimony that it is a correct representation of the object it purports to picture, since it purports to show' only shadows of objects not otherwise visible to the eye. To authenticate an X-ray picture two things are generally required: (1) It must be shown that the picture offered is actually a picture of the object or part of the body of which it is claimed to be a picture. (2) It must be shown by satisfactory evidence that the picture is accurate, in the sense that it conforms to the standard of accuracy of X-ray pictures generally.” 32 C.J.S., Evidence, section 712.
Dr. Tannenbaum testified fully on his direct examination that in his opinion the plaintiff was suffering from hysteria. Counsel for the defendant undertook to have him repeat this identical testimony on his re-direct examination, and the trial court sustained the objection of plaintiff to such repetition. The ninth, tenth, twelfth, thirteenth, and fourteenth exceptions, which question this ruling, are not maintainable. A trial court has discretionary power to exclude or limit the repetition *286of questions and answers, however proper such questions and answers may have been in the first instance. In re Smith’s Will, 163 N.C. 464, 79 S.E. 977; 70 C.J., Witnesses, section 861.
Due to inadvertency in transcription, the second issue was originally submitted to the jury in these words: “Did the defendant, by his own negligence, contribute to his injury?” After deliberating for an hour and twenty minutes, but before answering any of the issues, the jury returned into open court, and called the trial judge’s attention to the typographical mistake. The judge forthwith reformed the issue by substituting the word “plaintiff” for the term “defendant,” and the jury resumed its deliberations. At that time the defendant noted her eighteenth exception to the “action of the trial court in submitting an erroneous and incorrect issue of contributory negligence to the jury, and in thereafter making a correction of the issue after the jury had been deliberating for an hour and twenty minutes.”
Nothing in the record indicates that the defendant was prejudiced in any way by the original wording of the second issue, or by its subsequent rephrasing by the trial judge. For this reason, the eighteenth exception is overruled.
The sixteenth, seventeenth, nineteenth, and twentieth exceptions are directed to the charge, and to a statement of the trial court to the jury concerning views on the law expressed by counsel for defendant at a time when the jury returned into the courtroom and requested further instruction on a particular phase of the law relating to contributory negligence. These assignments of error cannot be sustained.
The statement of the judge was tantamount to an admonition that the jury should take the law from the court rather than from counsel. The instructions on contributory negligence, which the defendant challenges, conformed to repeated decisions of this Court. McKinnon v. Motor Lines, 228 N.C. 132, 44 S.E. 2d 735; Roberson v. Taxi Service, Inc., 214 N.C. 624, 200 S.E. 363; Cashatt v. Brown, 211 N.C. 367, 190 S.E. 480; Liske v. Walton, 198 N.C. 741, 153 S.E. 318; Davis v. Jeffreys, 197 N.C. 712, 150 S.E. 488; Bailey v. R. R., 196 N.C. 515, 146 S.E. 135; Elder v. R. R., 194 N.C. 617, 140 S.E. 298; Boswell v. Hosiery Mills, 191 N.C. 549, 132 S.E. 598; Construction Co. v. R. R., 185 N.C. 43, 116 S.E. 3; Construction Co. v. R. R., 184 N.C. 179, 113 S.E. 672. Moreover, the instructions as to proximate causation were correct, and made it plain to the jury that foreseeability of injury is an essential element of proximate cause in the law of negligence. Shaw v. Barnard, 229 N.C. 713, 51 S.E. 2d 295; Wood v. Telephone Co., 228 N.C. 605, 46 S.E. 2d 717; Nichols v. R. R., 228 N.C. 222, 44 S.E. 2d 879; Boyette v. R. R., 227 N.C. 406, 42 S.E. 2d 462; Lee v. Upholstery Co., 227 N.C. 88, 40 S.E. 2d 688; Rattley v. Powell, 223 N.C. 134, 25 S.E. 2d 448; Montgomery v. Blades, *287222 N.C. 463, 23 S.E. 2d 844, rehearing denied in 223 N.C. 331, 26 S.E. 2d 567; Luttrell v. Mineral Co., 220 N.C. 782, 18 S.E. 2d 412.
Tbe twenty-first and twenty-second exceptions are formal, and require no discussion.
Tbe judgment will be upheld; for tliere is in law