In exactly five minutes by his watch Adrian gave the prisoner a rough shake.
"You know what I said?"
The man nodded his head.
"Well, I am now going to take out your gag. If you make more than one cry, or utter more than one word, your own knife will finish you."
He held the knife before the man's eyes. Then with the knife in one hand, Adrian pulled the wad of grass from between the prisoner's teeth.
No sooner had the man drawn one long breath than he let out a yell that might have been heard half a mile and which he was about to repeat with variations, when with a swift movement, Adrian forced the grass back into his mouth and the yell died in a dismal gurgle.
"I ought to use the knife," said Adrian, "but I guess this will do."
With a bound he sprang to his feet and dashed to where Donald was already performing his part of the work.
The plan had worked exactly as Adrian had figured, and in another moment the boys were astride the horses and away toward Vera Cruz.
But one thing they had not taken into consideration. That single yell of their erstwhile prisoner had aroused the Mexican pickets and from half a dozen directions came the sound of rifle shots and then the sound of a bugle calling to arms.