Order affirmed, without costs of this appeal to either party. Memorandum: We think that the court should have instructed the physician, who had treated defendant and whom defendant called as a witness, to answer certain questions which the physician had refused to answer upon the ground that he had not received compensation to testify as an expert. A physician, when subpoenaed, must attend court and may be required to testify to what he knows. "As to any fact within the knowledge of a professional witness, he stands upon an equality with every other witness. But it is well settled that a physician and surgeon meets the requirements of a subpoena when he appears in court and gives impromptu answers to such questions as may be put to him. He cannot be required, as such physician and surgeon, to examine into the case and use his skill and knowledge so as to form an opinion." ( Mount v. Welsh, 118 Or. 568, 585; 247 P. 815.) We are of the opinion, however, that this and other errors of which the defendant complains would not justify a reversal of the order which is amply supported by the evidence. All concur. (The order directs defendant to contribute to the support of an infant in a filiation proceeding.)