parent, and the balance is restored. Monas, euglena, uvella, cryptomonas, gonium, and other wondrous infusoria, may be detected as constituents of the cloudy mass while it lasts, called into being because the conditions of the tank were such as they required; as if life in embryo was everywhere locked up until the moment came for its liberation, and some particular circumstance was the talisman to set it free; or if we consider created forms to be marshalled in grand procession, may we not expect that every tribe will hurry to its appointed place the instant that a door is opened?

Microscopists have long been at war, but without bloodshed, as to the place to be assigned to certain organic forms which are hidden from our common eyesight. While the war goes on as to whether desmidiacæ and diatomaceæ be animal or vegetable, or both, let facts suffice us here in the study of the aquarium. Does an animal exhale carbonic acid? Yes. Well, here are plants or animals, concerned in keeping up the balance, which exhale oxygen, and their name is legion. Volvox globator and the bacillariæ labour as hard to supply the fishes with the life-sustaining gas as do the silken threads of verdure that line the glass like a carpet. Is the possession of starch a distinctive feature of the vegetable? Perhaps so. Truly here are desmidiacæ that contain starch, and if I make the possession of cilia the test for assigning certain forms to the animal kingdom, I find in the aquarium spores of algae furnished with them. Motion I know to be no test, because algæ spores dance through the water gaily till they find a resting-place, and when the aquarium was first filled,

it was by dancing they at last found where to pitch their tents, and cease their nomad wanderings. But they all work together to sustain the balance, and the law of "give and take" prevails amongst them-the stentor devours the oscillatoriæ, rotatoria, and monads, and the hydras swallow all; every darting speck is a tomb wherein some smaller speck of life is to be buried, and life thus prospers on the decay it is itself undergoing.

But all this while a fine deposit slowly settles among the pebbles, which form the lower stratum of this watery world. Between the stones a fine alluvial silt collects and thickens. The first frost, sufficiently severe to touch the tank, causes the whole green coating to peel off from the glass and rock, and while this subsides, to add to the thickness of the alluvium-how slightly, and yet how sufficiently for an example of Nature's working! -a new growth commences, and that balance is restored. Do you not see that the chief teaching of geology-the piling of stratum upon stratum, the conversion of disrupted rock and decayed plant and animal into rock again-is here exemplified in the history of a domestic toy, which contains already one example of stratification in the silence of watery submergence? A tank which has been fitted with loam, pebbles, and plants of the brook and river, will, if left undisturbed for three years, be in this state. Those plants will all have decayed, but there will be an abundant spontaneous vegetation. The accumulations of that short period will have settled into a close mass, almost as hard as stone; and if fishes have died in the meantime, and have not been removed, their bones will be found overlaid with hardened mud, just

as we find them in the old red sandstone, or the chalk, or the carboniferous rocks, and shall we not call them our own fossils? See again in this case in which death has been very busy (for plants of large growth soon perish in the absence of sunshine, and occasional attendant accidents will carry off some of the finny pets), how life has been equally active on the other side, for such an aquarium will be a hundred times richer in those spontaneous growths we have already spoken of, and visible forms of infusoria and true zoophytes will abound, and every class will be more fully represented, down even to the twilight monad.

Though this paper must have an end, there is no end to the teaching of the aquarium. It is a watery microcosm of living and dead wonders, and we need not marvel that the balance of life and death may be observed in its succession of changes, because all the physical forces of the universe are locked up within a single bead of dew, and all the functions of organic creation are comprised in the economy of monas termo. If God so ordains that life shall be constantly soaring from the tomb, if the story of the Phoenix ceases to be a fable, need man, the victim of doubts and fears, ever fail in his trust of that blessed promise, that "this mortal shall put on immortality, and this corruptible shall put on incorruption?" Science may fix his mind on the appreciation of God's wisdom and power as he reads the handwriting of the Almighty in Nature, but through faith in another revelation must he hope to exclaim, triumphantly, "O death, where is thy sting? O grave, where is thy victory ?" Or, to pass from divine to human consolations, we may

take up the apostrophe of the great Raleigh, and say, "O eloquent, just, and mighty Death! what none have dared, thou hast done; what none have attempted, thou hast accomplished; thou hast gathered all the might, majesty, and meanness of mankind, and hast covered them with these two words, hic jacet." Nature's children have a dread of death, but Nature herself is in friendly compact with the master of silence. If the types, which are the ideas of God, have survived from the oldest rocks to this present hour, will not the spirit, which lives on ideas, and evolves them as the aquarium evolves its throng of animalcules, live for ever? It is not hard to believe with Tennyson :

"That nothing walks with aimless feet,

That not one life shall be destroyed,

Or cast as rubbish to the void,

When God hath made the pile complete."

"The pile" will be complete when God's purpose is fulfilled in man, to whom it is given to hope after eternal life, and with eyes of faith to pierce through the veil, and behold the wondrous things of eternity.

156

THE POETRY OF CHEMISTRY.

"There's not one atom of yon earth

But once was living man;

Nor the minutest drop of rain,

That hangeth in the thinnest cloud,

But flowed in human veins."

SHELLEY.

So pass and change the elements of the world. So separate and combine, so decay and revivify, so come and go the creatures of the earth and air, and in due time all the particles of the rounded world pass through the life current of the human heart. Nature is a great laboratory, a necromantic palace of mutation. Yet out of all this passing and repassing, this flitting and fading of her dead and living children, she still preserves the old familiar face, and looks upon us with the same sweet mother's smile which gladdened the hearts of the old thinkers, and cheered the builders of the ancient temples. Nature has but a few simple materials, and neither crucible nor alembic in which to elaborate her new forms, and yet with this poverty of means does she trick out all the world in scenes of delicious beauty, and hedge round the waking thoughts of men with wonder upon wonder. "The whole code of her laws may be written on the thumb-nail, or the signet of a ring.

The whirling