She had seen many cowboy breakers of wild horses; she knew the confident bearing of them; the quickness with which they adjusted their muscles to the eccentric movements of the horse under them, anticipating their every action, so far as anyone was able to anticipate the actions of a rage-maddened demon who has only one desire, to kill or maim its rider, and she knew that Calumet was an expert.

He was cool, first of all, in spite of his grimness; he kept his temper, he was absolutely without fear; he was implacable, inexorable in his determination to conquer.
Somehow the battle between horse and man, as it raged up and down before her, sometimes shifting to the far end of the level, sometimes coming so near that she could see the expression of Calumet's face plainly, seemed to be a contest between kindred spirits.

The analogy, perhaps, might not have been perceived by anyone less intimately acquainted with Calumet, or by anyone who understood a horse less, but she saw it, and knowing Calumet's innate savagery, his primal stubbornness, his passions, the naked soul of the man, she began to feel that the black was waging a hopeless struggle.

He could never win unless some accident happened.
And they were very near her when it seemed that an accident did happen.
The black, his tongue now hanging out, the foam that issued from his mouth flecked with blood; his sides in a lather; his flanks moist and torn from the cruel spur-points: seemed to be losing his cunning and to be trusting entirely to his strength and yielding to his rage.

She could hear his breath coming shrilly as he tore past her; the whites of his eyes white no longer, but red with the murder lust.