The legal effect of orders of the Interstate Commerce Commission involves questions upon which there has been much dictum and considerable confusion of the issues. The result has been a body of law which, if not carefully explored, may prove to be a trap for the unwary. In the past few years, however, it is apparent that the courts are making more definite pronouncements which are more clearly pointing the way to distinguishing the various possible issues. The confusion unquestionably results from the heterogeneous nature of the functions performed by the Commission. A typical example is the rate-making function. It has been frequently held and is now accepted as Jaw that the Commission in prescribing rates for the future is exercising a legislative function, but that when it awards reparations for excessive charges made in the past it is exercising a quasi-judicial function. Obviously the pronouncements of a legislature and of a court, respectively, have different legal effects and, by analogy, the pronouncements of the Interstate Commerce Commission must have different legal effects when legislative powers are exercised than when quasi-judicial powers are exercised. Yet it is not safe to say that a legislative order of the Commission has the same force and effect as a statute, or that a quasi-judicial order of the Commission has the same force and effect as a judicial decision.