The question is here a difficult one; but a little more study [p326] of the general habits of fishes, merely as we know them already, and even of their anatomy, will go far to lay the foundation of useful rules on this head, even without a hazardous trial, which may ultimately not become in our power to remedy, as I much fear may prove the case with respect to these unlucky basse. Not to enter on this further than as it may serve for a general illustration of what is here meant, the anatomy of the mullet proves that it lives on worms; on the lumbricus marinus, and others; and so do its habits. So also may the very food of others, as found in the stomach, serve to indicate their natural or ordinary food. Reversely, the anatomy of a cod’s jaws, and its stomach also, prove it to be omnivorous, omnivoracious. Or, further, the anatomical character of the diodon proves that it eats shell-fish; as we are equally able to limit the range of food in the flat-fish which have no air-bladders, and cannot quit the ground. But in this brief communication, I must not enter further into this subject than is necessary for mere illustration. I may take some further opportunity to point out the probabilities, as to mutual food and protection, in any artificial cultivation of this nature, as they might be derived from studying the little that we do know about the structure and habits of fishes. All that I need add here, is, that I have suggested the introduction of limpets, periwinkles, and cockles; as affording food without furnishing enemies: a matter which had been overlooked. To exterminate the enemies which have been unwarily introduced, will not prove so easy a task; unless, at least, we could find their natural enemies; find the great secret by which alone, in all cases, man can make war on those whom neither his artillery, his physic, nor his politics can reach.