"Chum," he said confusedly, "it don't make sense to me, not even yet. I don't get the hang of it. But I know this much: I know you got ten times the sense what I'VE got. Where you got it an' how you got it the good Lord only knows. But you've got it. I--I was figgerin' on lickin' you 'most to death, a few minutes back. Chum. Honest, I was. I'm clean 'shamed to look you in the face when I think of it. Say! Do me a favor, Chum. If ever I lift hand to lick you, jes' bite me and give me hydrophoby. For I'll sure be deservin' it. Now come on home!" He patted the silken head of the jubilant dog as he talked, rumpling the soft ears and stroking the long, blazed muzzle. He was sick at heart at memory of his recent murderous rage at this wonder-comrade of his. Chum was exultantly happy. He had had a most exhilarating ten minutes. The jolliest bit of fun he could remember in all his two years of life. The sight of those queer sheep--yes, and the scent of them, especially the scent--had done queer things to his brain; had aroused a million sleeping ancestral memories. He had understood perfectly well his master's order that he leave them alone. And he had been disappointed by it. He himself had not known clearly what it was he would have liked to do to them. But he had known he and they ought to have some sort of relationship. And then at the gesture and the snarled command of "Go get them!" some closed door in Chum's mind had swung wide, and, acting on an instinct he himself did not understand, he had hurled himself into the gay task of rounding up the flock. So, for a thousand generations on the Scottish hills, had Chum's ancestors earned their right to live. And so through successive generations had they imbued their progeny with that accomplishment until it had become a primal instinct. Even as the unbroken pointer of the best type knows by instinct the rudiments of his work in the field so will many a collie take up sheep herding by ancestral training. There had been nothing wonderful in Chum's exploit. Hundreds of untrained collies have done the same thing on their first sight of sheep. The craving to chase and slay sheep is a mere perversion of this olden instinct; just as the disorderly "flushing" and scattering of bird coveys is a perversion of the pointer or setter instinct. Chum, luckily for himself and for his master's flock, chanced to run true to form in this matter of heredity, instead of inheriting his tendency in the form of a taste for sheep murder. The first collie, back in prehistoric days, was the first dog with the wit to know his master's sheep apart from all other sheep. Perhaps that is the best, if least scientific, theory of the collie's origin. But to Link Ferris's unsophisticated eyes the achievement was all but supernatural, and it doubled his love for the dog.