Sir Walter Scott immortalized the sagacity of a dog named Yarrow, who was the accomplice of his master, Millar, a shepherd, and of Murdison, a farmer, in the sheep-stealing expeditions which they carried on, more than a century ago, in the Tweed country. All that Millar had to do was to show Yarrow during the day the sheep which were to be stolen, and at night the dog made straight for the flock, got together the marked members of it, and drove them by roundabout paths to Murdison's farm.

Two things were particularly remarkable. In the first place, if Yarrow when thus employed met his master, he observed the utmost caution in recognizing him, lest he might make him the object of suspicion; in the second, the dog seemed to have an idea that his practice was dishonest, and that darkness was the fittest season for such deeds. In the event of the sheep proving unwilling to leave their pasture, Yarrow would use every effort to urge them onwards, but whenever day began to break, he abandoned the attempt.

The dog was said to have been hanged with his master, for sheep-stealing, but Sir Walter Scott states that this was not the case, and that he survived Millar a long time, though he did not exhibit any of his wonderful instinct when in his second master's possession. Of course it was a great crime to put his skill to such a bad use, but there can be no doubt that Yarrow's sagacity fully justified Sir Walter in describing him as an "accomplished" dog.