The first proposition is to the effect that the legislation of the Provincial Parliament of the Dominion, so long as it strictly relates to subjects of legislation expressly enumerated in section 91, is of paramount authority, even though it trenches upon matters assigned to the Provincial 175 Legislatures by section 92, Lord Tomlin referred to Tennant vs Union Bank of Canada, supra, as the authority for this statement." Viscount Caldecote then observed: "In applying these principles, as their Lordships propose to do, an inquiry must first be made as to the "true nature and character of the enactment in question" Citizen Insurance Co. Of Canada vs Wiliam Parsons) (supra) or, to use Lord Watson 's words in delivering the judgment of the Judicial Committee in Union Colliery Company of British Columbia vs Bryden(1) as to their "pith and substance".