Joe sprang to his feet at the sound of his chum's voice. He had come ashore, after splashing around in the water, and, for the moment, Blake was alone in the river.

As Joe looked he saw a black, ugly snout, and back of it a glistening, black and knobby body, moving along after Blake, who was making frantic efforts to get out of the way.

"I'm coming, Blake! I'm coming!" cried Joe, as he ran to the edge of the stream, with the intention of plunging in.

"You will be too late," declared Mr. Alcando. "The alligator will have him before you reach him. Oh, that I was a good swimmer, or that I had a weapon."

But Joe did not stay to hear what he said. But one idea was in his mind, that of rescuing his chum from peril. That he might not be in time never occurred to him.

Blake gave a gurgling cry, threw up his hands, and disappeared from sight as Joe plunged in to go to his rescue.

"It's got him—the beast has him!" cried the Spaniard, excitedly.

"No, not yet. I guess maybe he sank: to fool the alligator," said the guide, an educated Indian named Ramo. "I wonder if I can stop him with one shot?" he went on, taking up a powerful rifle that had been brought with the camp equipment.

Joe was swimming out with all his power, Blake was nowhere to be seen, and the alligator was in plain sight, heading for the spot where Blake had last been observed.

"It's my only chance!" muttered Ramo. "I hope the boy stays under water."

As he spoke the guide raised the rifle, took quick but careful aim, and fired. There was no puff of smoke, for the new high-powered, smokeless powder was used. Following the shot, there was a commotion in the water. Amid a smother of foam, bright red showed.

"You hit him, Ramo!" cried the Spaniard. "You hit him!"

"I guess I did," the Indian answered. "But where is Blake?"

That was what Joe was asking himself as he plunged on through the stream, using the Australian crawl stroke, which takes one through the water at such speed. Just what Joe could do when he reached his chum he did not stop to think. Certainly the two would have been no match for the big alligator.

But the monster had met his match in the steel-jacketed mushrooming bullet. It had struck true and after a death struggle the horrid creature sank beneath the surface just as Blake shot up, having stayed under as long as he could.

"All right, Blake! Here you are! I'm with you!" cried Joe, changing his course to bring himself to his chum. "Are you all right?"

"Yes, except for this cramp. The alligator didn't get near enough to do any damage. But where is he?"

"Ramo shot him," answered Joe, for he had seen the creature sink to its death. "You're all right now. Put your hand on my shoulder, and I'll tow you in."

"Guess you'll have to. I can't seem to swim. I dived down when I saw how near the beast was getting, thinking I might fool him. I hated to come up, but I had to," Blake panted.

"Well, you're all right now," Joe assured him, "but it was a close call. How did it happen?"

"I'm sure I don't know," said Blake, still out of breath from trying to swim under water. "If I'd known there were alligators in this river I'd never have gone so far from shore."

"That's right," agreed Joe, looking around as though to make sure no more of the creatures were in sight.

He saw none. On the shore stood Ramo, the guide, with ready rifle.

"Feel better now?" asked Joe.

"Yes, the cramp seems to be leaving me. I think I went in swimming too soon after eating those plantains," for they had been given some of the yellow bananas by a native when they stopped at his hut for some water. "They upset me," Blake explained. "I was swimming about, waiting for you to come back and join me, when I saw what I thought was a log in the water. When it headed for me I thought it was funny, and then, when I saw what it was, I realized I'd better be getting back to shore. I tried, but was taken with a fierce cramp. You heard me just in time."

"Yes," responded Joe, as he and Blake reached water shallow enough to wade in, "but if it hadn't been for Ramo's gun—well, there might be a different story to tell."

"And one that wouldn't look nice in moving pictures," Blake went on with a laugh. "You did me a good turn," he said to Ramo a little later, as he shook hands with the dusky guide. "I shan't forget it."

"Oh, it wasn't anything to pop over an alligator that way," Ramo returned. "I've often done it for sport. Though I will admit I was a bit nervous this time, for fear of hitting you."

"I wish I had been the one to shoot it," said the Spaniard.

"Why?" asked Joe, as he sat down on the warm sandy bank of the stream to rest.

"Why, then I should have repaid, in a small measure, the debt I am under to you boys for saving my life. I shall never forget that."

"It wasn't anything," declared Blake quickly. "I mean, what we did for you."

"It meant a great deal—to me," returned the Spaniard quietly, but with considerable meaning in his tone. "Perhaps I shall soon be able to—but no matter. Are there many alligators in this stream?" he asked of Ramo.

"Oh, yes, more or less, just as there are in most of the Panaman rivers. But I never knew one to be so bold as to attack any one in daylight. Mostly they take dogs, pigs, or something like that. This must have been a big, hungry one."

"You'd have thought so if you were as close to him as I was," spoke Blake with a little shudder.

No one else felt like going in swimming just then, and the two boys dressed. Blake had fully recovered from the cramp that had so nearly been his undoing.

For a week longer they lived in the jungle, moving from place to place, camping in different locations and enjoying as much as they could the life in the wild. Blake and Joe made some good moving picture films, Mr. Alcando helping them, for he was rapidly learning how to work the cameras.

But the views, of course, were not as good as those the boys had obtained when in the African jungle. These of the Panama wilds, however, were useful as showing the kind of country through which the Canal ran, and, as such, they were of value in the series of films.

"Well, we'll soon be afloat again," remarked Blake, one night, when they had started back for Gamboa. "I've had about enough jungle."

"And so have I," agreed Joe, for the last two days it had rained, and they were wet and miserable. They could get no pictures.

Their tug was waiting for them as arranged and, once more on board, they resumed their trip through the Canal.

Soon after leaving Gamboa the vessel entered a part of the waterway, on either side of which towered a high hill through which had been dug a great gash.

"Culebra Cut!" cried Blake, as he saw, in the distance Gold Hill, the highest point. "We must get some pictures of this, Joe."

"That's right, so we must. Whew! It is a big cut all right!" he went on. "No wonder they said it was harder work here than at the Gatun Dam. And it's here where those big slides have been?"

"Yes, and there may be again," said Blake.

"I hope not!" exclaimed Captain Watson. "They are not only dangerous, but they do terrible damage to the Canal and the machinery. We want no more slides."

"But some are predicted," Blake remarked.

"Yes, I know they say they come every so often. But now it would take a pretty big one to do much damage. We have nearly tamed Culebra."

"If there came a big slide here it would block the Canal," observed Mr. Alcando, speculatively.

"Yes, but what would cause a slide?" asked the captain.

"Dynamite could do it," was the low-voiced answer.

"Dynamite? Yes, but that is guarded against," the commander said. "We are taking no chances. Now, boys, you get a good view of Culebra," and he pointed ahead. Blake and Joe were soon busy with their cameras, making different sets of views.

"Hand me that other roll of film; will you, please?" asked Blake of the Spaniard, who was helping them. "Mine is used up."

As Mr. Alcando passed over the box he muttered, though possibly he was unaware of it:

"Yes, dynamite here, or at the dam, would do the work."

"What—what's that?" cried Blake, in surprise.