From The Mountains of California IV

From Chapter 7, The Glacier Meadows:

The influences of pure nature seem to be so little known as yet, that it is generally supposed that complete pleasure of this kind, permeating one’s very flesh and bones, unfits the student for scientific pursuits in which cool judgement and observation are required. But the effect is just the opposite. Instead of producing a dissipated condition, the mind is fertilized and stimulated and developed like sun-fed plants.