One of the most curious enemies of our freshwater fishes is a small floating water-weed, the bladderwort. Along its branchlets are a number of small green vesicles or bladders, which, being furnished with minute jaws, seize upon tiny fish, which are assimilated into its substance. This is a subtle poacher, the true character of which has only lately been detected. The bladderwort is a fairly common plant, and no very special interest attached to it ere its fish-eating propensities were discovered. Its tiny vesicles were known to contain air, and the only use of these so far as was known was to keep the plant afloat--a belief, be it remarked, all the more reasonable because many aquatic plants actually have such air receptacles for that very purpose. The tiny bladders attached to the leaves and leaf-stalks are each furnished with a door, the whole acting on the eel-trap principle, entrance being easy but exit impossible. There is nothing very formidable about the delicate green jaws of the vegetable trap, only that any tiny water creature that ventures in to look round out of mere curiosity never by any chance emerges alive. The first time that the bladder-wort was actually caught at its fish-poaching proclivities, so to speak, was by Professor Moseley, of Oxford. He and a friend had, in a large glass bowl, a plant of this species and also a number of young roach just hatched. The murderous plant held several of the tiny fish in its jaws; and upon an experiment being tried in a separate vessel, it was found that a single plant had captured no less than a dozen fish in the space of six hours. One of these was caught by the head, another by the tail, a third by the yolk-sac, and in another instance two bladders had seized the same fish, one holding on at each extremity. In spite of all this tiny ferocity it must be admitted that this little plant poacher is more interesting than dangerous, and so long as it confines its attention to coarse fish neither the salmon-fisher nor trout-angler will concern himself much about its aquatic depredations.