vessel, and on the surface of the water. To meet this emergency, Mr. Warington introduced a few common Pond-snails (Limnea), which greedily fed on the decaying vegetable matter and slimy mucous growth, so as quickly to restore the whole to a healthy state.
The result was now quite satisfactory. The plant throve and increased greatly by offshoots and suckers; the fishes continued to preserve their health and beauty, while the snails deposited enormous masses of eggs, thus supplying food for the fishes, as well as performing the office of scavengers.
Thus the success of the experiment was established, and an Aquarium was formed in fresh water; which has continued to prosper to the present time; the animals and plants maintaining each other in healthy life, and the water preserving its purity unchanged.
In January, 1852, Mr. Warington began to prosecute experiments of the same kind with sea-water, which presented some difficulties arising from the compound nature of that fluid, and from the peculiarities of marine vegetation. These difficulties, however, yielded to the perseverance and skill of the operator, and while I write these lines I am personal witness to his complete success, having just seen (January 1854) specimens of Sea-anemones and other marine animals in good health in that gentleman's Aquarium, which I know were sent from the sea-side more than a year and a quarter ago.
A Memoir by Mr. Warington, which appeared in the "Annals of Natural History" for November, 1853, gives some very interesting details of the progress of
