The thesis is divided into four sections. The first section lays down a method of interpretation of S.91 and S.92 of the B.N.A. Act. The suggested method is comprised of making three enquiries:- Is the statute in question within S.92---is the statute within a S.91 enumerated power and is the statute within the residuary general power? The validity of this method rests on four propositions viz:- S.91 comprises the residue of powers after the provinces have been given certain basic heads of powers; the enumerated powers in S.91 are supreme over those contained in S.92; where the subject matter of the statute in question goes beyond local or provincial concern or interest it will fall within the general federal power under S.91 even though it might otherwise appear to come within S.92; where neither S.92 nor S.91 enumerated powers apply the statute in question falls under the residuary federal power in S.91. Each one of these propositions is examined and supported. The second section deals with the general rules of construction of the powers in S.91 and S.92. The matter is approached from the idea of a dichotomy between factors and formulae in constitutional interpretation. The factors are those matters that guide the court in answering the questions posed in the first section and the formulae are the rationales given for the decisions. This approach is inseverably connected with the concept of constitutional decisions being evaluative judgments. The evaluative judgment made in answering the original questions is referred to as the 'nexus' judgment. The place of precedent, evidence and extrinsic material in relation to the factors is then examined and the general ideas prevalent in Canadian constitutional interpretation such as the double aspect, ancillary, trenching, paramountcy and severability doctrines are looked at in the light of this 'nexus' judgment. The strength and identity of the factors will vary from individual power to power and the criminal law power is adopted as an illustration of the use of the factorial approach. This illustrative use comprises the third section of the thesis. The lack of logical limits to the power is first shown and then the general factors of construction, purpose and effect are used to provide a basis for constitutional prediction. The evaluation of factors is viewed both from the standpoint of federal legislation and that of the provinces. No attempt is made to give an exhaustive survey of the interpretation of the criminal law power. It is merely given as an illustration of the use of the factorial approach. The final section is the conclusion and recapitulates the major principles contained in the earlier sections. / Law, Peter A. Allard School of / Graduate