And in the meanwhile, among this animal forest grows a vegetable one of delicatest sea-weeds, green and brown and crimson, whose office is, by their everlasting breath, to reoxygenate the impure water, and render it fit once more to be breathed by the higher animals who swim or creep around.
Mystery of mysteries! Let us jest no more, - Heaven forgive us if we have jested too much on so simple a matter as that poor spider- crab, taken out of the lobster-pots, and left to die at the bottom of the boat, because his more aristocratic cousins of the blue and purple armour will not enter the trap while he is within.
I am not aware whether the surmise, that these tiny zoophytes help to purify the water by exhaling oxygen gas, has yet been verified. The infusorial animalcules do so, reversing the functions of animal life, andinstead of evolving carbonic acid gas, as other animals do, evolve pure oxygen. So, at least, says Liebig, who states that he found a small piece of matchwood, just extinguished, burst out again into a flame on being immersed in the bubbles given out by these living atomies.
I myself should be inclined to doubt that this is the case with zoophytes, having found water in which they were growing (unless, of course, sea-weeds were present) to be peculiarly ready to become foul; but it is difficult to say whether this is owing to their deoxygenating the water while alive, like other animals, or to the fact that it is very rare to get a specimen of zoophyte in which a large number of the polypes have not been killed in the transit home, or at least so far knocked about, that (in the Anthozoa, which are far the most abundant) the polype - or rather living mouth, for it is little more - is thrown off to decay, pending the growth of a fresh one in the same cell.
But all the sea-weeds, in common with other vegetables, perform this function continually, and thus maintain the water in which they grow in a state fit to support animal life.
This fact - first advanced by Priestley and Ingenhousz, and though doubted by the great Ellis, satisfactorily ascertained by Professor Daubeny, Mr. Ward, Dr. Johnston, and Mr. Warrington - gives an answer to the question, which I hope has ere now arisen in the minds of some of my readers, -How is it possible to see these wonders at home? Beautiful and instructive as they may be, can they be meant for any but dwellers by the sea-side? Nay more, even to them, must not the glories of the water- world be always more momentary than those of the rainbow, a mere Fata Morgana which breaks up and vanishes before the eyes? If there were but some method of making a miniature sea-world for a few days; much more of keeping one with us when far inland. -This desideratum has at last been filled up; and science has shown, as usual, that by simply obeying Nature, we may conquer her, even so far as to have our miniature sea, of artificial salt-water, filled with living plants and sea-weeds, maintaining each other in perfect health, and each following, as far as is possible in a confined space, its natural habits.
To Dr. Johnston is due, as far as is known, the honour of the first accomplishment of this as of a hundred other zoological triumphs. As early as 1842, he proved to himself the vegetable nature of the common pink Coralline, which fringes every rock-pool, by keeping it for eight weeks in unchanged salt-water, without any putrefaction ensuing. The ground, of course, on which the proof rested in this case was, that if the coralline were, as had often been thought, a zoophyte, the water would become corrupt, and poisonous to the life of the small animals in the same jar; and that its remaining fresh argued that the coralline had re- oxygenated it from time to time, and was therefore a vegetable.
In 1850, Mr. Robert Warrington communicated to the Chemical Society the results of a year's experiments, "On the Adjustment of the Relations between the Animal and Vegetable Kingdoms, by which the Vital Functions of both are permanently maintained." The law which his experiments verified was the same as that on which Mr. Ward, in 1842, founded his invaluable proposal for increasing the purity of the air in large towns, by planting trees and cultivating flowers in rooms, THAT THEANIMALANDVEGETABLERESPIRATIONSMIGHTCOUNTERBALANCE EACH OTHER; the animal's blood being purified by the oxygen given off by the plants, the plants fed by the carbonic acid breathed out by the animals.
On the same principle, Mr. Warrington first kept, for many months, in a vase of unchanged water, two small gold fish and a plant of Vallisneria spiralis; and two years afterwards began a similar experiment with sea-water, weeds, and anemones, which were, at last, as successful as the former ones. Mr. Gosse had, in the meanwhile, with tolerable success begun a similar method, unaware of what Mr. Warrington had done; and now the beautiful and curious exhibition of fresh and salt water tanks in the Zoological Gardens in London, bids fair to be copied in every similar institution, and we hope in many private houses, throughout the kingdom.
To this subject Mr. Gosse's book, "The Aquarium," is principally devoted, though it contains, besides, sketches of coast scenery, in his usual charming style, and descriptions of rare sea-animals, with wise andgoodly reflections thereon. One great object of interest in the book is the last chapter, which treats fully of the making and stocking these salt- water "Aquaria;" and the various beautifully coloured plates, which are, as it were, sketches from the interior of tanks, are well fitted to excite the desire of all readers to possess such gorgeous living pictures, if as nothing else, still as drawing-room ornaments, flower-gardens which never wither, fairy lakes of perpetual calm which no storm blackens, -[Greek text which cannot be reproduced]
