The liability of parties on negotiable instruments executed by agents or representatives is a matter which has not been satisfactorily settled by the cases under the N.I.L., due partly to the ambiguity of the statute itself and partly to the obstinate refusal of some courts to adopt the approach of the ordinary business man. Under the law merchant the agent ran a great risk of personal liability in executing a negotiable instrument unless he was careful to spell out that he was signing for a named principal as agent only. If he merely added to his name the phrase "agent of X" or the word "president" when his name appeared under that of the corporation, the court was likely to hark back to ancient times and say that the addition was mere descriptio personae, or, as a slight concession to more modern practices, that it was prima facie descriptive and thus subject to proof by extrinsic evidence of its being representative.