Can oral evidence be used to vary the bond?

Counsel for the bank takes the position that oral evidence is not admissible to vary the bond, and relies on the authority of Can. Bk. of Commerce v. Cherry, 1928 CanLII 111 (SK CA), [1928] 4 D.L.R. 87, 23 S.L.R. 189, [1928] 2 W.W.R. 662. The principle enunciated in that case has no application here for the simple reason that counsel for the bank first introduced evidence in an endeavour to show that no such undertaking was entered into. Evidently this was done in anticipation of evidence to be introduced by the defendant. Whatever the reason was, by introducing the evidence counsel for the plaintiff waived a right of objection which might otherwise have been available to him. In any case, at the trial the evidence of the defendant was not objected to. The point was raised only in a written brief submitted by counsel for the bank.