A tiny crevice in some high cliff is not infrequently chosen by these fascinating little plants, which protect themselves from drought by assuming a mantle of light wool, or of hair and chaff, with, perhaps, a covering of white powder as in some cloak fernsthus keeping a layer of moist air next to the surface of the leaf, and checking transpiration.

Exercise, he held, increases transpiration; transpiration shortens life; to live long, then, we need only remain perfectly still.