"The infinitesimal seedlings became a forest of trees that grew courteously, correcting the distances between themselves as they shaped themselves to the promptings of available light and moisture, tempering the climate and the temperaments of the Scots, as the driest land became moist and the wettest land became dry, seedlings finding a mean between extremes, and the trees constructing a moderate zone for themselves even into what I would have called tundra, until I understood the fact that Aristotle taught, while walking in a botanic garden, that the middle is fittest to discern the extremes."