We should treat our minds, that is, ourselves, as innocent and ingenuous children, whose guardians we are, and be careful what objects and what subjects we thrust on their attention.
Henry David ThoreauTo preserve wild animals implies generally the creation of a forest for them to dwell in or resort to. So it is with man. A hundred years ago they sold bark in our streets peeled from our own woods. In the very aspect of those primitive and rugged trees there was, methinks, a tanning principle which hardened and consolidated the fibres of men's thoughts. Ah! already I shudder for these comparatively degenerate days of my native village, when you cannot collect a load of bark of good thickness, and we no longer produce tar and turpentine.
Henry David Thoreau