Without the aid of the pencil it is indeed scarcely possible to give an adequate idea of the magnificence of this vegetation, especially of the manner in which the different forms are grouped. We may see, it is true, in our own hot-houses, well-trimmed palms, beautiful orchids with their abnormal blossoms, and Aroideae with their bright, sappy, sometimes regularly perforated, leaves; but how different is this from the virgin forest, wherein Nature, undisturbed by man, has created her own prodigies, and where no narrow pots separate her children from the maternal soil, and where no dim roof of glass intervenes between them and the blue ether! Nor, in our carefully tended hot-houses, is the eye ever gratified with such agreeable contrasts as are afforded by the silver-gray and rust-brown tints of the decayed leaf of the palm or the fern-tree, or the black bark of the rotting trunk, with the blazing scarlet of some heliconia blossom. How difficult it must be to give to every plant, especially to orchids, the exact quantity of light, warmth, and moisture it requires, can be understood only by those who have seen clusters of them hidden in the deep shade of the tree-crowns, while others are exposed to the scorching rays of the sun in the vicinity of a river or in some clearer part of the forest; some species thriving on the bare rock almost, and others clinging fast with their white rootlets to the moist rotting bark of a tree.... But of far greater importance to the half-civilized riverines than either palms or orchids, for whose beauties they have no eye, are the cacao and the caoutchouc-tree (_Siphonia elastica_), products of the virgin forest essential to the future prosperity of the whole country. Although India contributes to the supply of caoutchouc, the precious resin which is transformed into a thousand different shapes every year in the factories of Europe and North America, and sent to the ends of the earth, it cannot compete with Brazil, which takes the first place among the rubber-producing countries, in respect as well of the vastness of its export of the material as of its superior quality. On the shores of the Amazon its production, it is true, has already been diminished by unreasonable treatment of the trees; the idea of replacing the old ones by young saplings never having presented itself, apparently, to the mind of the indolent population; but the seringaes, or woods of rubber-trees, on the banks of the Madeira, the Purus, and other tributaries of the main river, still continue to furnish extraordinary quantities of it. The province of Amazon alone exports more than fifty thousand arrobas (one million six hundred thousand pounds) yearly, while the total of the exports of the whole basin slightly exceeds four hundred thousand arrobas, or twelve million eight hundred thousand pounds, per annum....