He was nearly used up, and it was hard work to run—­very hard work; and nothing but the instinct of self-preservation enabled him to keep the tall and wiry form of the Zouave in sight.  They reached the ravine, where the water was about three feet deep.  The shot, and shell, and bullets still fell in showers around them, and occasionally one of the luckless fugitives was struck down.  They crossed the stream, and continued on their flight.  An officer on horseback dashed by them, and bade them run with all their might, or they would be taken.

“For Heaven’s sake, get me some water!” said a rebel, who was wounded in the leg, to a Zouave, who passed near him.

“You are a rebel, but I will do that for you,” replied the Zouave; and he gave him a canteen filled with water.

The rebel drank a long, deep draught, and then levelled his musket at the head of his Samaritan enemy and fired.  This transaction had occupied but a moment, and Tom saw the whole.  His blood froze with horror at the unparalleled atrocity of the act.  The Zouave, whom Tom had followed, uttered a terrible oath, and snatching the musket from the hands of the soldier boy, he rushed upon the soulless miscreant, and transfixed him upon the bayonet.  Uttering fierce curses all the time, he plunged the bayonet again and again into the vitals of the rebel, till life was extinct.

“Boy, I used to be human once,” said the Zouave, when he had executed this summary justice upon the rebel; “but I’m not human now.  I’m all devil.”

“What a wretch that rebel was!” exclaimed Tom, who seemed to breathe freer now that retribution had overtaken the viper.

“A wretch!  Haven’t you got any bigger word than that, boy?  He was a fiend!  But we mustn’t stop here.”

“I thought the rebels were human.”

“Human?  That isn’t the first time to-day I’ve seen such a thing as that done.  Come along, my boy; come along.”

Tom followed the Zouave again; but he was too much exhausted to run any farther.  Even the terrors of the Black Horse Cavalry could not inspire him with strength and courage to continue his flight at any swifter pace than a walk.

“I can go no farther,” said he, at last.

“Yes, you can; pull up! pull up!  You will be taken if you stop here.”

“I can’t help it.  I can go no farther.  I am used up.”

“Pull up, pull up, my boy!”

“I can’t.”

“But I don’t want to leave you here.  They’ll murder you—­cut your throat, like a dog.”

“I will hide myself in the bushes till I get a little more strength.”

“Try it a little longer.  You are too good a fellow to be butchered like a calf,” added the generous Zouave.

But it was no use to plead with him, for exhausted nature refused to support him, and he dropped upon the ground like a log.

“Poor fellow!  I would carry you in my arms if I could.”