the individual; yet these gradual changes are extremely slow. Between steps of noticeable change there elapse periods many times longer than the life of historic man. All speed in changes such as these comes in what we call 'sports'. That is, a particular plant, for instance, gradually tends to have fewer leaves and a thicker bark, but the change is slight from age to age until suddenly a single instance occurs of plant which realises suddenly in a single step the 'ideal' towards which the species has been striving. In a word, it has very, very few leaves, and an extraordinarily thick bark.
"For a particular instance, one species of orange tended to have few and fewer seeds. But finally came an orange tree whose fruit had no seeds at all. That was the origin of the navel orange. And that was a typical 'sport'.
"Now, there is the reverse of the sport. Instead of jumping long distance ahead, an individual may lapse back towards the primitive. That individual is called an atavism. For instance, in this mountain-desert there has, for several generations, been a pressure of environment calling for a species of man which will be able to live with comparative comfort in a waste region—a man, in a word, equipped with such powerful organisms that he will be as much at home in the heart of the desert as an ordinary man would be in a drawing-room. You gather the drift of my argument.
"I have observed this man Barry carefully. I am thoroughly convinced that he is such an atavism.
"Among other men he seems strange. He is different and therefore he seems mysterious. As a matter of fact, he is quite a common freak. I could name you others like him in differing from common men, though not differing from them in exactly the same manner.
"You see the result of this? Daniel Barry is a man to whom the desert is necessary, because he was made for the desert. He is lonely among crowds—you have said it yourself—but he is at home in a mountain wilderness with a horse and a dog."
"Doc, you talk well," broke in Joe Cumberland, "but if he ain't human, why do humans like him so much? Why does he mean so much to me—to Kate?"
"Simply because he is different. You get from him what you could get from no other man in the world, perhaps, and you fail to see that the fellow is really more akin to his wolf-dog than he is to a man."
"Supposin' I said you was right," murmured the old man, frowning, "how d'you explain why he likes other folks. According to you, the desert and the mountains and animals is what he wants. Then how is it that he took so much care of me when he come back this time? How is it that he likes Kate, enough to give up a trail of blood to stay here with her?"
"It is easy to explain the girl's attraction," said the doctor. "All animals wish to mate, Mr. Cumberland, and an age-old instinct is now working out in Dan Barry. But while you and Kate may please him, you are not necessary to him. He left you once before and he was quite happy in his desert. And I tell you, Mr. Cumberland, that he will leave you again. You cannot tame the untameable. It is not habit that rules this man. It is instinct a million years old. The call which he will hear is the call of the wilderness, and to answer it he will leave father and wife and children and ride out with his horse and his dog!"
The old man lay quite motionless, staring at the ceiling.
"I don't want to believe you," he said slowly, "but before God I think you're right. Oh, lad, why was I bound up in a tangle like this one? And Kate—what will she do?"
The doctor was quivering with excitement.
"Let the man stay with her. In time she will come to see the brute nature of Daniel Barry. That will be the end of him with her."
"Brute. Doc. They ain't nobody as gentle as Dan!"
"Till he tastes blood, a lion can be raised like a house-dog," answered the doctor.
"Then she mustn't marry him? Ay, I've felt it—jest what you've put in words. It's livin' death for Kate if she marries him! She's kept him here to-day. To-morrow something may cross him, and the minute he feels the pull of it, he'll be off on the trail—the blow of a man, the hollering out of the wild geese—God knows what it'll take to start him wild again and forget us all—jest the way a child forgets its parents!"
A voice broke in upon them, calling far away: "Dan! Dan Barry!"
XXXIV. THE ACID TEST
In the living-room below they heard it, Dan and Kate Cumberland. All day she had sat by the fire which still blazed on the hearth, replenished from time to time by the care of Wung Lu. She had taken up some sewing, and she worked at it steadily. Some of that time Dan Barry was in the room, sitting through long intervals, watching her with lynx-eyed attention. Very rarely did he speak—almost never, and she could have numbered upon her two hands the words he had spoken—ay, and she could have repeated them one by one. Now and again he rose and went out, and the wolf-dog went with him each time. But towards the last Black Bart preferred to stay in the room, crouched in front of her and blinking at the fire, as if he knew that each time his master would return to the fire. Then, why leave the pleasant warmth for the chilly greyness of the day outside?
There he remained, stirring only now and then to lift a clumsy paw and brush it across his eyes in an oddly human gesture. Once or twice, also, he lifted that great, scarred head and laid it on her knees, looking curiously from her busy hands to her face, and from her face back again to her work, until, having apparently assured himself that all was well, he dropped his head again and lay once more motionless. She could see him open a listless eye when the master entered the room again. And with each coming of Dan Barry she felt again surrounded as if by invisible arms. Something was prying at her, striving to win a secret from her.
As the day wore on, a great, singing happiness rose in her throat, and at about the same time she heard a faint sound, impalpable, from the farther side of the room where Dan Barry sat. He was whistling.
A simple thing for a man to do, to be sure, but the astonishment of it nearly stopped the heart of Kate Cumberland. For in all her life she had never before heard him whistle except when he was in the open, and preferably when he was astride of the strength and the speed of Satan, with Black Bart scouting swiftly and smoothly ahead. But now he whistled here by the warmth of the fire. To be sure the sound was small and thin, but there was such music in it as she had never heard before. It was so thin that it was almost ghostly, as if the soul of wild Paganini played here on a muted violin. No tune that might be repeated, but as always when she heard it, a picture rose before the eyes of Kate. It wavered at first against the yellow glow of the firelight. Then it quite shut out all else.
It was deep night, starry night. The black horse and his rider wound up a deep ravine. To one side a bold mountain tumbled up to an infinite height, bristling with misshapen trees here and there, and losing its head against the very stars. On the other side were jagged hills, all carved in the solid rock. And down the valley, between the mountains and the stars, blew a soft wind; as if that wind made the music. They were climbing up, up, up, and now they reach—the music rising also to a soft but triumphant outburst—a high plateau. They were pressed up against the heart of the sky. The stars burned low, and low. Around them the whole earth seemed in prospect at their feet. The moon burst through a mass of clouds, and she saw, far off, a great river running silver through the night.
Happy? Ay, and he was happy too, and his happiness was one with hers. He was not even looking out the window while he whistled, but his eyes were fixed steadily, unchangingly, upon her face.
It was then that they heard it: "Dan! Dan Barry!
