In the present case, it is not the case of either party that the first situation is attracted. So far as the second circumstance noticed above is concerned, question of exercise of due diligence would not arise because the concerned scientific laboratory from which examination is sought to be made itself was not in existence at the time of trial and so that clause is also not attracted. In the third circumstance the appellate court may require any document to be produced or any witness to be examined to enable it to pronounce judgment, or for any other substantial cause. The expression to enable it to pronounce judgment has been subject of several decisions including Syed Abdul Khader v. Rami Reddy & Ors., AIR 1979 SC 553 wherein it was held that when the appellate court finds itself unable to pronounce judgment owing to a lacuna or defect in the evidence as it stands, it may admit additional evidence. The ability to pronounce a judgment is to be understood as the ability to pronounce a judgment satisfactory to the mind of court delivering it. It is only a lacuna in the evidence that will empower the court to admit additional evidence [ See : The Municipal Corporation of Greater Bombay v. Lala Pancham & Ors., AIR 1965 SC 1008]. But a mere difficulty in coming to a decision is not sufficient for admission of evidence under this rule. The words or for any other substantial cause must be read with the word requires, which is set out at the commencement of the provision, so that it is only where, for any other substantial cause, the appellate court requires additional evidence, that this rule would apply as noticed by the Privy Council in Kesowji Issur v. G.I.P.Railway [supra]. It is under these circumstances such a power could be exercised. Therefore, when the first appellate court did not find the necessity to allow the application, we fail to understand as to how the High Court could, in exercise of its power under Section 115 CPC, could have interfered with such an order, particularly when the whole appeal is not before the court. It is