The employer appeals from the decision of the Superior Court directing judgment on a compensation award. The facts are stated in the opinion of the Superior Court which is reported in 156 Pa. Superior Ct. 644, 41 A. 2d 425.

Appellant contends that the record does not contain sufficient evidence to support a finding that aggrava *140 tion of pre-existing osteo-arthritis, separate and apart from the normal progress of that disease, caused total disability. Two physicians so testified. The value of their evidence was for the triers of fact, whose findings, being supported by that evidence, are binding on the court.

We have read and considered the entire record in the light of appellant’s argument but find no occasion to discuss various objections to the opinion evidence given by the two physicians, Nash and Leech: see, generally, Wig-more, Vol. 3 (3rd ed.), section 687. If there was any deviation from the strict technical rule the error was harmless. We may supplement the opinion of the Superior Court by stating that both witnesses accepted X-rays as disclosing the visible evidence of the basis of their opinions, the aggravation being inferred from the nature of the “bone production” shown on the X-ray, as distinguished from what would have shown if it resulted from the natural progress of the disease.

We affirm the judgment on the opinion of the Superior Court.

Judgment affirmed.