"How interesting it is to reflect on the minuteness of the organs by which the largest plants are fed and sustained. Microscopic apertures in the leaf suck in gaseous food from the air; the surfaces of microscopic hairs suck a liquid food from the soil. We are accustomed to admire, with natural and just astonishment, how huge, rocky reefs, hundreds of miles in length, can be built up by the conjoined labors of myriads of minute zoophytes, laboring together on the surface of a coral rock; but it is not less wonderful that, by the ceaseless working of similar microscopic agencies in leaf and root, the substance of vast forests should be built up and made to grow before our eyes. It is more wonderful, in fact; for whereas, in the one case, the chief result is that, dead matter extracted from the sea is transformed into a dead rock; in the other, the lifeless matter of the earth and air are converted by these minute plant-builders into living forms, lifting their heads aloft to the sky, waving with every wind that blows, and beautifying whole continents with the varying verdure of their ever-changing leaves." Further on in the same chapter, on pages 62-3, the same eloquent writer continues: "But the special chemical changes that go on within the plant, could we follow them, would appear not less wonderful than the rapid production of entire microscopic vegetables from the raw food contained in the juice of the grape. It is as yet altogether incomprehensible, even to the most refined physiological chemistry, how, from the same food taken in from the air, and from generally similar food drawn up from the soil, different plants, and different parts of plants, should be able to extract or produce substances so very different from each other in composition and in all of their properties. From the seed-vessels of one (the poppy) we collect a juice which dries up into our commercial opium; from the bark of another (cinchona) we extract the quinine with which we assuage the raging fever; from the leaves of others, like those of hemlock and tobacco, we distil deadly poisons, often of rare value for their medicinal uses. The flowers and leaves of some yield volatile oils, which we delight in for their odors and their aromatic qualities; the seeds of others give fixed oils, which are prized for the table or use in the arts * * * These, and a thousand other similar facts, tell us how wonderfully varied are the changes which the same original forms of matter undergo in the interior of living plants. Indeed, whether we regard the vegetable as a whole, or examine its minutest part, we find equal evidence of the same diversity of changes and of the same production, in comparatively minute quantities, of very different, yet often characteristic forms of matter."