But where growth is on a stupendous scale, there decay is exuberant, for “the powers that build are the powers that putrefy.” Above are light, warmth, and moisture: such are conditions of growth. Below are darkness, warmth, and moisture: such are conditions of decay. Which is more effectual, that mighty power of evolution elaborating “the rain-water hurrying aloft” into tissue of leaf and flower, or those great forces of dissolution which can so soon transmute the fallen trunk of iron-wood into a pregnant, humid mound? It merely lapses into those elements composing it, and is instantly absorbed by fresh leaves culminating to-night. The noble heat blends the smell of laboring sap and that of aromatic mosses with the pungent odor of decay, the damp smell of death with those sweet poisons which drip off the trees and envelop like a caress. The incense tree was described by Martin Fernandez de Enciza in the early sixteenth century. “Incense doth hang at its boughs,” he said, “as the ice doth at the tiles of a house in the winter season.” Over-ripe fruit drops smashing on the ground with scent of strawberries. A musky humming-bird leaves behind a thin trail of heady perfume. The air is filled with vegetable breath, weird, far-off blossoms, mere ghosts of fragrance mingling in a wave of sweetness. Smell is indeed man’s most emotional sense. It gives a poignancy to a remembered scene which no detailed picture can, and sharpens the whole sight perception. An entire chapter should be written about jungle-perfume. The silence of day is succeeded by the “soundless tune” that fills the night. It surges up from below and shuts down from above. Pervasive as the murmuring of water, it spreads out through the night, pierced by a sudden brilliant squeak near at hand. With darkness settles a humming, booming, drumming, croaking, deafening uproar from thousands of diversified insect throats filling up every chink of space, each one crowding out the other. Insects here are not a miniature, far-off chorus, one ingredient of a summer night, but overwhelming, terrifying, absorbing the dark atmosphere. Mysterious animals live in the depths of the ocean where no ray of light has ever pierced. They light the way for their own fishing, as the glow-worm is struck by its own brightness before seeing any other. Fire-beetles and phosphorescent caterpillars and flickering fireflies--little stitches of a shining thread in the soft, verdured blackness of the tepid night--make the primeval forest discernible.