1                                 What, however, is presently significant is that the community of interest had its source in the assignment of the lease as to part of the land to X and part to Y and that the attached common burden was imposed by the law respecting distraint.  The equity in favour of X to recover the share of the rent from Y had arisen from the operation of the law upon their situation, not by some looser notion of economic interest which disregards or supersedes the legal framework within which the parties chose to have their dealings.

2                                 In that sense it is true to say that here, as elsewhere, equity looks to substance and not merely to legal form when it fixes upon the legal situation of the parties and requires that the exercise of legal rights produce a result which conforms to equitable doctrine.  But that is not to adopt the wider statement made in the present case by Mason P that the equitable doctrine of contribution "is not confined by legal structures"[1].  That view of the jurisdiction provides a framework of analysis at too high a level of abstraction, and risks a result discordant with accepted principle and the general coherence of the law[2].  In a case such as the present, to proceed in this way may too easily produce an outcome in a given case which is no more than an idiosyncratic exercise of discretion.