Then the combatants fell out—­literally.  Up from the solid earth between the twisted roots they seemed to come, but that proved the art of one of them in concealing his front-door from the curious, and down the bank of the sea-wall, over and over and over, squeaking the most murderous language, and grappling like pocket-devils—­tumbled a little jet-black and a little dark-brown beast.

They continued the duel upon the dry gravel below—­the finest and the whitest gravel ever you did see—­and they would apparently have gone on for goodness knows how long if a gray-white, thin, worn post a couple of yards away had not turned into a heron and stalked an ungainly stalk towards them.

Then they fell apart, and one of them, at any rate—­the brown one—­ran away in the shape of a water-vole—­water-"rat,” if you will—­the heron making spear-lunges at him with his bill as he ungainlily skipped at the other’s tail all the way up the bank.  The other fighter, the black one, could not rightly be said to have turned into anything very much—­at least, not anything that any one could swear to.  It just seemed as if a dark blur whizzed about—­more bird-like than beast-like—­around the astonished and prancing heron, and then into nowhere.  It was like watching a blue-bottle in a tumbler, and very extraordinary.  The heron never even professed to follow it or lunge at it.  He preferred the water-vole, whose agility was not too fast to see.

At the place where it had come from, the mouth of the hole, it stopped—­this beast that could move quicker than eye could follow—­stopped so suddenly and completely that its change from almost lightning motion to stony motionlessness in the fraction of a second was nearly as amazing as its first marvelous exhibition.  It stopped, I say, and became a—­a rat.

To nine hundred and ninety-nine people out of a thousand, the word “rat” conveys only one impression.  This rat did not fulfill that impression.  In fact, there is more than one kind of rat, and though fate and their fathers’ Kismet has cursed them all with a name of shame, they are not all the kind of people that made it so.  There is the foreigner, the invader, the common brown rat, who is accursed; there is the old English black rat, whom the accursed one has nearly wiped out into little more than a ghost; and there is the water-rat, who is not a rat, but a vole, and would thank you to remember the fact.

And this rat was a black rat, as black as jet, shark-jawed, star-eyed, elfin-eared, snake-tailed, lean, long-legged, and graceful—­a very greyhound among the rats.  He was there, in that dancing-floor of the winds by the estuary, because no common or sewer rats were there.  They were anathema to him, and they were worse—­death in many horrible forms.  He had been there all the summer, all the autumn, and all the——­ No, by whiskers! he was not going to remain there all the winter.  He had his limit, and he hated cold; and here, down by the flat, sodden, mud-choked shore of the estuary, it was so cold that if you didn’t jolly well mind what you were up to and keep your tummy always full, you went to sleep, and—­never woke up any more.