5. ..... Therefore, the burden initially rests on the plaintiff who has to prove that the promissory note was executed by the defendant. As soon as the execution of the promissory note is proved the rule of presumption laid down in Section.118 of the Negotiable Instruments Act helps him to shift the burden to the other side. The burden of proof as a question of law rests, therefore, on the plaintiff; but as soon as the execution is proved, Section 118 of the Negotiable Instruments Act imposes a duty on the court to raise a presumption in his favour that the said instrument was made for consideration. This presumption shifts the burden of proof in the second sense, that is, the burden of establishing a case shifts to the defendant. The defendant may adduce direct evidence to prove that the promissory note was not supported by consideration, and if he adduced acceptable evidence, the burden again shifts to the plaintiff, and so on. The defendant may also rely upon circumstantial evidence and, if the circumstances so relied upon are compelling, the burden may likewise shift again to the plaintiff. He may also rely upon presumptions of fact, for instance those mentioned in Section 114 and other sections of the Evidence Act. Under Section 114 of the Evidence Act.