There he sits, twiddling his feelers (a substitute, it seems, with crustacea for biting their nails when they are puzzled), and by no means lovely to look on in vulgar eyes; - about the bigness of a man's fist; a round-bodied, spindle-shanked, crusty, prickly, dirty fellow, with a villanous squint, too, in those little bony eyes, which never look for a moment both the same way. Never mind: many a man of genius is ungainly enough; and Nature, if you will observe, as if to make up to him for his uncomeliness, has arrayed him as Solomon in all his glory never was arrayed, and so fulfilled one of the proposals of old Fourier - that scavengers, chimney-sweeps, and other workers in disgusting employments, should be rewarded for their self-sacrifice in behalf of the public weal by some peculiar badge of honour, or laurel crown. Not that his crown, like those of the old Greek games, is a mere useless badge;on the contrary, his robe of state is composed of his fellow-servants. His whole back is covered with a little grey forest of branching hairs, fine as a spider's web, each branchlet carrying its little pearly ringed club, each club its rose-coloured polype, like (to quote Mr. Gosse's comparison) the unexpanded birds of the acacia. On that leg grows, amid another copse of the grey polypes, a delicate straw-coloured Sertularia, branch on branch of tiny double combs, each tooth of the comb being a tube containing a living flower; on another leg another Sertularia, coarser, but still beautiful; and round it again has trained itself, parasitic on the parasite, plant upon plant of glass ivy, bearing crystal bells, each of which, too, protrudes its living flower; on another leg is a fresh species, like a little heather-bush of whitest ivory, and every needle leaf a polype cell - let us stop before the imagination grows dizzy with the contemplation of those myriads of beautiful atomies. And what is their use? Each living flower, each polype mouth is feeding fast, sweeping into itself, by the perpetual currents caused by the delicate fringes upon its rays (so minute these last, that their motion only betrays their presence), each tiniest atom of decaying matter in the surrounding water, to convert it, by some wondrous alchemy, into fresh cells and buds, and either build up a fresh branch in their thousand-tenanted tree, or form an egg-cell, from whence when ripe may issue, not a fixed zoophyte, but a free swimming animal.
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, and instead 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.
