business undisturbed, under the protection of the bark-cells. The cells of the fundamental tissue, which is inhabited by the working people proper, unite in close association; between them courses, with numerous branches, a system of canals, which are connected with each other like net-work, and find their exit through the clefts. In this manner the air which they require for food and respiration is introduced to the cells, and by the same road escape the gases and vapors which the cells throw off, and which need to be removed.
The fluid foods are carried to the working-cells through the vascular tissue in a special system of ducts, conduits, and fibers, which, joined in strings and bundles, penetrate all the organs, the roots, stock, limbs, and leaves, and are known as the ducts, or vascular bundles; they may be most easily perceived in the leaves when held against the light, where they form the most beautiful vein-work. These conducting vessels are also traffic-roads, in which the products of the working cells of the main tissue are transported to other places, where they are put to use. Thus an unceasing activity, like that of the bee-hive, prevails in the cell-state of the plant. Gases go in and out; juices circulate up and down, absorption and evaporation, distillation and refining, forming anew, remodeling, or destroying the old, are going on all the time without rest or cessation for an instant. As long as the cells live, they are active; when they cease to work, their death is near. No one thinks, when he looks at a plant, what restless activity is at work within it, for the cells perform their artful labor in stillness, without buzzing and flying around as the bees do.
The wealth of those lands that possess coal-mines and ore-beds is highly prized. But these treasures are not confined to single provinces. Immense mines of ore, inexhaustible coal-beds, surround us wherever we may be. For the minerals that are contained in the field soils are quite as precious as are the mines of iron and zinc, yes, even of gold and silver. Man can not live on gold and silver; but out of the minerals of the field-soil, out of potash, lime, phosphoric acid, ammonia, and sulphuric acid, the cell-state of the plant prepares bread on which we live, linen in which we clothe ourselves, wood out of which we make our vessels and tools, and the remedies which when we are sick restore our lost health to us. The cells of the roots, like hewers and miners, sink numerous shafts in the spaces assigned to them, drive their galleries toward all points of the compass, in order to break up these mineral treasures, separate them from the incasing stone, and set the machinery of service in motion; day and night with inexhaustible diligence, they extract atom by atom of potash and ammonia, phosphoric and nitric acid, and, without working up their ore, deliver it over to the conducting vessels which transmit it by their powerful system of sucking and forcing pumps to the stem and the leaves. The leaves are cell-villages which perform their daily tasks in the air and the light. Their principal business is to obtain coal, which is the chief