But the most repulsive of the destructive results of human expansion is the poisoning of rivers, and the consequent extinction in them of fish and of well-nigh every living thing, save mould and putrefactive bacteria. In the Thames it will soon be a hundred years since man, by his filthy proceedings, banished the glorious salmon, and murdered the innocents of the eel-fare. Even at its foulest time, however, the Thames mud was blood-red (really "blood-red," since the colour was due to the same blood-crystals which colour our own blood) with the swarms of a delicate little worm like the earth-worm, which has an exceptional power of living in foul water, and nourishing itself upon putrid mud. In old days I have stood on Hungerford Suspension Bridge and seen the mud-banks as a great red band of colour, stretching for a mile along the picture when the tide was low. In smaller streams, especially in the mining and manufacturing districts of England, progressive money-making man has converted the most beautiful things of nature--trout streams--into absolutely dead corrosive chemical sewers. The sight of one of these death-stricken black filth-gutters makes one shudder as the picture rises, in one's mind, of a world in which all the rivers and the waters of the sea-shore will be thus dedicated to acrid sterility, and the meadows and hill-sides will be drenched with nauseating chemical manures. Such a state of things is possibly in store for future generations of men! It is not "science" that will be to blame for these horrors, but should they come about they will be due to the reckless greed and the mere insect-like increase of humanity. * * * * *