Whenever any person has been examined as a witness in any civil matter before any tribunal of this Commonwealth or conducted by virtue of its order or direction, if such witness afterwards dies, or is out of the jurisdiction so that he cannot be effectively served with a subpoena, or if he cannot be found, or if he becomes incompetent to testify for any legally sufficient reason, and if the party, against whom notes of the testimony of such witness are offered, had actual or constructive notice of the examination and an opportunity to be present and examine or cross-examine, properly proven notes of the examination of such witness shall be competent evidence in any civil issue which may exist at the time of his examination, or which may be afterwards formed between the same parties and involving the same subject-matter as that upon which such witness was so examined. For the purpose of contradicting a witness, the testimony given by him in another or in a former proceeding may be orally proved.