It is impossible to speak of insects or molluscs without naming these animalcules, which seem to be their rough outline, and in the extreme simplicity of their organism already foretoken, indicate, and prepare for them. With a good microscope you can discern these miniatures of the insect, which simulate their organism, and mimic their movements. When you are able to distinguish the _Rotifers_, you think that in the aggregations and in the tentacles of their mouth you recognize them as little polypes. The _Rhizopods_, though almost imperceptible, are furnished, nevertheless, with good solid carapaces, which are equally as good a protection for them as their great shells are for the molluscs, the oyster and the snail. The microscopic _Tardigradæ_ are, in fact, closely connected with insects, and the _Acarina_ with worms. What are these least of the little? Simply the architects or builders of the globe which we inhabit. With their bodies and their remains they have prepared the soil now echoing under our feet. Whether their tiny shells be still distinguishable, or whether they have been decomposed into chalk, they are not the less the foundation of immense portions of our earth. A single bed of this chalk stretches from Paris to Tours; that is, for fifty miles. Another, of enormous breadth, spreads over all Champagne. Pure chalk, or Spanish white, which we find everywhere, is composed of pounded shells. And it is these most minute of organisms which have wrought the grandest of works. The imperceptible rhizopod has built for itself a nobler monument than the Pyramids; nothing less than Central Italy, a notable portion of the chain of the Apennines. But even this was too insignificant: the colossal masses of Chili, the prodigious Cordilleras, which look down upon the world at their feet, are the funeral monument wherein this impalpable--I had almost said invisible-organism has interred the remains of its vanished race. A bygone world, hidden beneath the present and upper world in the profundities of life or the obscurity of time! What might it not tell us, if God would give it speech, and permit it to recall all that it has done or is doing for us! What just demands might not the elementary plants, the imperfect animals whose dust has fashioned for our use the fertile crust of the globe, that noble theatre of life, address to us! "While you were still asleep," might say the ferns, "we alone, by transforming and purifying the previously irrespirable air, created after thousands upon thousands of years the earth now blooming with the corn and the rose! We accumulated that subterranean treasure of enormous coal-beds which warms your hearth; and that one mass, among others, a hundred leagues in length, which feeds the great forge of the world from London to Newcastle."