They saw him marching out of camp, but they did not see the instant and terrible transformation which took place as soon as he was within the secrecy of the forest. He no longer marched. At once he became a thing of the wild, stealing along softly, cat-footed, a passing shadow that appeared and disappeared among the shadows. He knew how to take advantage of every cover, to crawl on his belly like a snake, and like a snake to leap and strike. He could take a ptarmigan from its nest, kill a rabbit as it slept, and snap in mid air the little chipmunks fleeing a second too late for the trees. Fish, in open pools, were not too quick for him; nor were beaver, mending their dams, too wary. He killed to eat, not from wantonness; but he preferred to eat what he killed himself. So a lurking humor ran through his deeds, and it was his delight to steal upon the squirrels, and, when he all but had them, to let them go, chattering in mortal fear to the treetops.

As the fall of the year came on, the moose appeared in greater abundance, moving slowly down to meet the winter in the lower and less rigorous valleys. Buck had already dragged down a stray part-grown calf; but he wished strongly for larger and more formidable quarry, and he came upon it one day on the divide at the head of the creek. A band of twenty moose had crossed over from the land of streams and timber, and chief among them was a great bull. He was in a savage temper, and, standing over six feet from the ground, was as formidable an antagonist as even Buck could desire. Back and forth the bull tossed his great palmated antlers, branching to fourteen points and embracing seven feet within the tips. His small eyes burned with a vicious and bitter light, while he roared with fury at sight of Buck.

From the bull’s side, just forward of the flank, protruded a feathered arrow-end, which accounted for his savageness. Guided by that instinct which came from the old hunting days of the primordial world, Buck proceeded to cut the bull out from the herd. It was no slight task. He would bark and dance about in front of the bull, just out of reach of the great antlers and of the terrible splay hoofs which could have stamped his life out with a single blow. Unable to turn his back on the fanged danger and go on, the bull would be driven into paroxysms of rage. At such moments he charged Buck, who retreated craftily, luring him on by a simulated inability to escape. But when he was thus separated from his fellows, two or three of the younger bulls would charge back upon Buck and enable the wounded bull to rejoin the herd.

There is a patience of the wild—dogged, tireless, persistent as life itself—that holds motionless for endless hours the spider in its web, the snake in its coils, the panther in its ambuscade; this patience belongs peculiarly to life when it hunts its living food; and it belonged to Buck as he clung to the flank of the herd, retarding its march, irritating the young bulls, worrying the cows with their half-grown calves, and driving the wounded bull mad with helpless rage. For half a day this continued. Buck multiplied himself, attacking from all sides, enveloping the herd in a whirlwind of menace, cutting out his victim as fast as it could rejoin its mates, wearing out the patience of creatures preyed upon, which is a lesser patience than that of creatures preying.

As the day wore along and the sun dropped to its bed in the northwest (the darkness had come back and the fall nights were six hours long), the young bulls retraced their steps more and more reluctantly to the aid of their beset leader. The down-coming winter was harrying them on to the lower levels, and it seemed they could never shake off this tireless creature that held them back. Besides, it was not the life of the herd, or of the young bulls, that was threatened. The life of only one member was demanded, which was a remoter interest than their lives, and in the end they were content to pay the toll.

As twilight fell the old bull stood with lowered head, watching his mates—the cows he had known, the calves he had fathered, the bulls he had mastered—as they shambled on at a rapid pace through the fading light. He could not follow, for before his nose leaped the merciless fanged terror that would not let him go. Three hundredweight more than half a ton he weighed; he had lived a long, strong life, full of fight and struggle, and at the end he faced death at the teeth of a creature whose head did not reach beyond his great knuckled knees.

From then on, night and day, Buck never left his prey, never gave it a moment’s rest, never permitted it to browse the leaves of trees or the shoots of young birch and willow. Nor did he give the wounded bull opportunity to slake his burning thirst in the slender trickling streams they crossed. Often, in desperation, he burst into long stretches of flight. At such times Buck did not attempt to stay him, but loped easily at his heels, satisfied with the way the game was played, lying down when the moose stood still, attacking him fiercely when he strove to eat or drink.

The great head drooped more and more under its tree of horns, and the shambling trot grew weak and weaker. He took to standing for long periods, with nose to the ground and dejected ears dropped limply; and Buck found more time in which to get water for himself and in which to rest. At such moments, panting with red lolling tongue and with eyes fixed upon the big bull, it appeared to Buck that a change was coming over the face of things. He could feel a new stir in the land. As the moose were coming into the land, other kinds of life were coming in. Forest and stream and air seemed palpitant with their presence. The news of it was borne in upon him, not by sight, or sound, or smell, but by some other and subtler sense. He heard nothing, saw nothing, yet knew that the land was somehow different; that through it strange things were afoot and ranging; and he resolved to investigate after he had finished the business in hand.

At last, at the end of the fourth day, he pulled the great moose down. For a day and a night he remained by the kill, eating and sleeping, turn and turn about. Then, rested, refreshed and strong, he turned his face toward camp and John Thornton. He broke into the long easy lope, and went on, hour after hour, never at loss for the tangled way, heading straight home through strange country with a certitude of direction that put man and his magnetic needle to shame.

As he held on he became more and more conscious of the new stir in the land. There was life abroad in it different from the life which had been there throughout the summer. No longer was this fact borne in upon him in some subtle, mysterious way. The birds talked of it, the squirrels chattered about it, the very breeze whispered of it. Several times he stopped and drew in the fresh morning air in great sniffs, reading a message which made him leap on with greater speed. He was oppressed with a sense of calamity happening, if it were not calamity already happened; and as he crossed the last watershed and dropped down into the valley toward camp, he proceeded with greater caution.

Three miles away he came upon a fresh trail that sent his neck hair rippling and bristling, It led straight toward camp and John Thornton. Buck hurried on, swiftly and stealthily, every nerve straining and tense, alert to the multitudinous details which told a story—all but the end. His nose gave him a varying description of the passage of the life on the heels of which he was travelling. He remarked the pregnant silence of the forest. The bird life had flitted. The squirrels were in hiding. One only he saw,—a sleek gray fellow, flattened against a gray dead limb so that he seemed a part of it, a woody excrescence upon the wood itself.

As Buck slid along with the obscureness of a gliding shadow, his nose was jerked suddenly to the side as though a positive force had gripped and pulled it. He followed the new scent into a thicket and found Nig. He was lying on his side, dead where he had dragged himself, an arrow protruding, head and feathers, from either side of his body.

A hundred yards farther on, Buck came upon one of the sled-dogs Thornton had bought in Dawson. This dog was thrashing about in a death-struggle, directly on the trail, and Buck passed around him without stopping. From the camp came the faint sound of many voices, rising and falling in a sing-song chant. Bellying forward to the edge of the clearing, he found Hans, lying on his face, feathered with arrows like a porcupine. At the same instant Buck peered out where the spruce-bough lodge had been and saw what made his hair leap straight up on his neck and shoulders. A gust of overpowering rage swept over him. He did not know that he growled, but he growled aloud with a terrible ferocity. For the last time in his life he allowed passion to usurp cunning and reason, and it was because of his great love for John Thornton that he lost his head.

The Yeehats were dancing about the wreckage of the spruce-bough lodge when they heard a fearful roaring and saw rushing upon them an animal the like of which they had never seen before. It was Buck, a live hurricane of fury, hurling himself upon them in a frenzy to destroy. He sprang at the foremost man (it was the chief of the Yeehats), ripping the throat wide open till the rent jugular spouted a fountain of blood. He did not pause to worry the victim, but ripped in passing, with the next bound tearing wide the throat of a second man. There was no withstanding him. He plunged about in their very midst, tearing, rending, destroying, in constant and terrific motion which defied the arrows they discharged at him. In fact, so inconceivably rapid were his movements, and so closely were the Indians tangled together, that they shot one another with the arrows; and one young hunter, hurling a spear at Buck in mid air, drove it through the chest of another hunter with such force that the point broke through the skin of the back and stood out beyond. Then a panic seized the Yeehats, and they fled in terror to the woods, proclaiming as they fled the advent of the Evil Spirit.

And truly Buck was the Fiend incarnate, raging at their heels and dragging them down like deer as they raced through the trees. It was a fateful day for the Yeehats. They scattered far and wide over the country, and it was not till a week later that the last of the survivors gathered together in a lower valley and counted their losses. As for Buck, wearying of the pursuit, he returned to the desolated camp. He found Pete where he had been killed in his blankets in the first moment of surprise. Thornton’s desperate struggle was fresh-written on the earth, and Buck scented every detail of it down to the edge of a deep pool. By the edge, head and fore feet in the water, lay Skeet, faithful to the last. The pool itself, muddy and discolored from the sluice boxes, effectually hid what it contained, and it contained John Thornton; for Buck followed his trace into the water, from which no trace led away.

All day Buck brooded by the pool or roamed restlessly about the camp. Death, as a cessation of movement, as a passing out and away from the lives of the living, he knew, and he knew John Thornton was dead. It left a great void in him, somewhat akin to hunger, but a void which ached and ached, and which food could not fill, At times, when he paused to contemplate the carcasses of the Yeehats, he forgot the pain of it; and at such times he was aware of a great pride in himself,—a pride greater than any he had yet experienced. He had killed man, the noblest game of all, and he had killed in the face of the law of club and fang. He sniffed the bodies curiously. They had died so easily. It was harder to kill a husky dog than them. They were no match at all, were it not for their arrows and spears and clubs. Thenceforward he would be unafraid of them except when they bore in their hands their arrows, spears, and clubs.

Night came on, and a full moon rose high over the trees into the sky, lighting the land till it lay bathed in ghostly day. And with the coming of the night, brooding and mourning by the pool, Buck became alive to a stirring of the new life in the forest other than that which the Yeehats had made, He stood up, listening and scenting. From far away drifted a faint, sharp yelp, followed by a chorus of similar sharp yelps. As the moments passed the yelps grew closer and louder. Again Buck knew them as things heard in that other world which persisted in his memory. He walked to the centre of the open space and listened. It was the call, the many-noted call, sounding more luringly and compellingly than ever before. And as never before, he was ready to obey. John Thornton was dead. The last tie was broken. Man and the claims of man no longer bound him.

Hunting their living meat, as the Yeehats were hunting it, on the flanks of the migrating moose, the wolf pack had at last crossed over from the land of streams and timber and invaded Buck’s valley. Into the clearing where the moonlight streamed, they poured in a silvery flood; and in the centre of the clearing stood Buck, motionless as a statue, waiting their coming. They were awed, so still and large he stood, and a moment’s pause fell, till the boldest one leaped straight for him. Like a flash Buck struck, breaking the neck. Then he stood, without movement, as before, the stricken wolf rolling in agony behind him. Three others tried it in sharp succession; and one after the other they drew back, streaming blood from slashed throats or shoulders.

This was sufficient to fling the whole pack forward, pell-mell, crowded together, blocked and confused by its eagerness to pull down the prey. Buck’s marvellous quickness and agility stood him in good stead. Pivoting on his hind legs, and snapping and gashing, he was everywhere at once, presenting a front which was apparently unbroken so swiftly did he whirl and guard from side to side. But to prevent them from getting behind him, he was forced back, down past the pool and into the creek bed, till he brought up against a high gravel bank. He worked along to a right angle in the bank which the men had made in the course of mining, and in this angle he came to bay, protected on three sides and with nothing to do but face the front.

And so well did he face it, that at the end of half an hour the wolves drew back discomfited. The tongues of all were out and lolling, the white fangs showing cruelly white in the moonlight. Some were lying down with heads raised and ears pricked forward; others stood on their feet, watching him; and still others were lapping water from the pool. One wolf, long and lean and gray, advanced cautiously, in a friendly manner, and Buck recognized the wild brother with whom he had run for a night and a day. He was whining softly, and, as Buck whined, they touched noses.

Then an old wolf, gaunt and battle-scarred, came forward. Buck writhed his lips into the preliminary of a snarl, but sniffed noses with him, Whereupon the old wolf sat down, pointed nose at the moon, and broke out the long wolf howl. The others sat down and howled. And now the call came to Buck in unmistakable accents. He, too, sat down and howled. This over, he came out of his angle and the pack crowded around him, sniffing in half-friendly, half-savage manner. The leaders lifted the yelp of the pack and sprang away into the woods. The wolves swung in behind, yelping in chorus. And Buck ran with them, side by side with the wild brother, yelping as he ran.

And here may well end the story of Buck. The years were not many when the Yeehats noted a change in the breed of timber wolves; for some were seen with splashes of brown on head and muzzle, and with a rift of white centring down the chest. But more remarkable than this, the Yeehats tell of a Ghost Dog that runs at the head of the pack. They are afraid of this Ghost Dog, for it has cunning greater than they, stealing from their camps in fierce winters, robbing their traps, slaying their dogs, and defying their bravest hunters.

Nay, the tale grows worse. Hunters there are who fail to return to the camp, and hunters there have been whom their tribesmen found with throats slashed cruelly open and with wolf prints about them in the snow greater than the prints of any wolf. Each fall, when the Yeehats follow the movement of the moose, there is a certain valley which they never enter. And women there are who become sad when the word goes over the fire of how the Evil Spirit came to select that valley for an abiding-place.

In the summers there is one visitor, however, to that valley, of which the Yeehats do not know. It is a great, gloriously coated wolf, like, and yet unlike, all other wolves. He crosses alone from the smiling timber land and comes down into an open space among the trees. Here a yellow stream flows from rotted moose-hide sacks and sinks into the ground, with long grasses growing through it and vegetable mould overrunning it and hiding its yellow from the sun; and here he muses for a time, howling once, long and mournfully, ere he departs.

But he is not always alone. When the long winter nights come on and the wolves follow their meat into the lower valleys, he may be seen running at the head of the pack through the pale moonlight or glimmering borealis, leaping gigantic above his fellows, his great throat a-bellow as he sings a song of the younger world, which is the song of the pack.