expand their feathery tufts in beauty, and the animals begin to take possession of their holes and corners, and to find themselves at home. But you must lay your account with the loss of some specimens; some will certainly die in the course of the first twenty-four hours, others in the first week. But those which survive the first ten days may be considered as pretty well established.
It is during this period that the grand trial of the experiment usually occurs. There is generally a large amount of animal matter attached to the sea-weeds, shells and stones, which are received from the sea, such as minute Annelida, Mollusca and Zoophytes: very many of these creatures are already dead, or die immediately; but being too minute to be detected and removed in detail, they decay, and presently contaminate the water. The first symptom of this is a slight dimming of the crystal translucency, which if unchecked soon increases to a milky whiteness, accompanied by a fetid odour, and terminates in the death of the whole animal collection.
Purification.—As soon as this begins to be perceived, the whole water should be drawn off by means of a siphon, without disturbing the sediment, into pans, into which for the present, the plants and animals may be put. The Tank should be wiped out and rinsed, and then the water should be filtered back into it. This is a very simple process: a funnel (if of glass, earthenware, or gutta-percha, the better) is placed over the tank, with a bit of sponge pushed lightly into the top of the tube, so as to allow the water to run through in a narrow thread-like stream
