and tried to soothe Domino by soft words. For once the
remedy failed to produce any immediate effect. The animal seemed
fairly wild, and tore along over the open country like mad.

"He never acted like this before in all his life," thought Bob, as he
found considerable difficulty in keeping his saddle, such were the
sudden whirls the black made in his erratic course.

But although he had by no means learned all the things known to old
cowmen, Bob had picked up quite a few points since arriving at the
ranch. He had even heard of a mean trick practiced by revengeful
Mexicans, and others, when they wished to place a rival's life in
danger.

"Something has happened to him since we went into that store," Bob said
again and again, as he puzzled his wits to hit upon an explanation for
the animal's remarkable antics. "Now, what could it have been? Would
any fellow be so mean as to fasten some of those prickly sand burrs
under his tail? Or perhaps it's a poison thorn under the saddle!"

This last idea seemed to strike him as pretty near the truth. He began
to investigate as well as he was able during the rushing of the runaway
horse. When, in pursuing his investigations, he ran his hand under the
flap of the saddle, he could feel the horse start afresh, and his queer
actions seemed worse than ever.

"That's just what it is, as sure as anything!" Bob declared, his whole
frame quivering with indignation at the thought of anyone being so
cruel and treacherous; "but how in the wide world am I going to get at
the thing?"

His first impulse was to ease the strain all he could by removing his
weight from the point where he believed the thorn to have been hidden.
This he did by leaning forward after the manner of a clever jockey in a
race, throwing pretty much all his body upon the shoulders and neck of
the horse.

Then he again began to speak soothingly in the ear of Domino. By
degrees the horse seemed to slacken his wild pace.

Encouraged by this fact, Bob continued the treatment. It appeared as
though the intelligent animal must comprehend what was wanted, for,
although evidently still in more or less pain, he gradually ceased his
runaway gait, until, finally, at the command of "whoa!" Domino came to
a complete stop.

Bob was on the ground immediately. His horse was trembling with
excitement and other causes. Bob continued to pat him gently, and
speak soothing words. All the time he was working toward the buc