When Dan saw that his face turned--I don't know how to say it!" She stopped a moment and her hands tightened.
"Back in his throat there came a sound that was almost like the snarl of Black Bart.

The wolf-dog watched him with a terror that was uncanny to see, the hair around his neck fairly on end, his teeth still bared, and his growl horrible.
"'Dan!' I called, 'don't go near him!' "I might as well have called out to a whirlwind.

He leaped.

Black Bart sprang to meet him with eyes green with fear.

I heard the loud click of his teeth as he snapped--and missed.