What is the test for reducing the verdict of a jury as to damages where there is no jury?

In Cosette v. Dun (1890) 1890 CanLII 39 (SCC), 18 SCR 222, Gwynne, J. stated at p. 257 the principle which should be followed by an appellate tribunal in considering the amount of damages awarded as follows: “ * * * that no court has any right to reduce the verdict of a jury as to damages where a jury is the tribunal, or of a judge adjudicating without a jury, on the ground of the damages being excessive in cases in which, like the present, the damages recoverable are not ascertainable by the application of any rule prescribing a measure of damages, or are not determinable by precise calculation, unless the damages awarded be so excessive, having regard to the evidence, as to shock the understanding of reasonable persons; to be so outrageous, in fact, that no reasonable twelve men, if the tribunal be a jury, could give; and that no judge, if a judge be the tribunal, could rationally give, that is without like shock to the understanding of reasonable persons.”