Take the sum of human achievement in action, in science, in art, in literature—subtract the work of the men above forty, and while we should miss great treasures, even priceless treasures, we would practically be where we are today … The effective, moving, vitalizing work of the world is done between the ages of twenty-five and forty.

Vol. I, Ch. 24 : "The Fixed Period'". - The Life of Sir William Osler (1925)