“OH, why did we have to wander so far away!” moaned Joe, rapidly losing his nerve. “We should have known better than to try to penetrate this endless jungle.”

Bob was equally touched, but he resolved to keep up hope. There was no use in tamely submitting to fear so soon. One more search might bring them to the river, and then it would be easy to find the boats.

“We’ll come out all right,” he said, “although I’ll admit we’re in a tight fix.”

The youths rested for nearly a half-hour. Then their strength—and to some extent their hope—restored, they again took up the task of finding the right trail.

Back and forth they hiked, confident that at last they would happen upon it. But search as they did, their efforts were in vain. The cruel Brazilian jungle was not to be conquered by man.

At last, satisfied that nothing could be gained by continuing such efforts, Joe moved that they take one of the other trails in the hope that it would lead them to the river.

“All right,” said Bob. “No use trying to find the one we followed when running from the jaguar.”

Joe had reloaded his rifle, and Bob had placed his hunting knife ready for instant use. They were taking no chances on meeting some formidable jungle beast.

The path that they now followed was wider than the others and consequently was more likely to lead to some definite spot. But neither of the chums was sure that they were heading for the river. It might lead them fifty miles away, for all they knew. Still they hiked on.

“Do you know,” remarked Bob, when another hour had passed, “that I’m beginning to think that these trails were not cut by wild animals! They’re too closely defined. Now take this one, for example. See how wide it is? And look over there. The vegetation’s been cut by a machete.”

Joe grew suddenly pale. He clutched his rifle tighter.

“You mean—savages?” he demanded, at the same time looking sharply about.

“I may be wrong,” Bob said quietly, “but that is my opinion. And as we’re about in the region inhabited by the savage tribe that Professor Bigelow was searching for, it seems that these paths could have been cut by them. What do you think?”

“I’m all too afraid that you’re right,” was the reply. “And we’ll have to be very careful from now on. At the slightest unfamiliar sound we’ll have to hide.”

Bob groaned.

“If I only had my rifle,” he cried. “Or if I had brought my revolver it wouldn’t be quite as bad.”

But there was no use regretting something that could not be helped, and Bob and Joe resolved to meet conditions as they were. Perhaps if it should happen that Indians discovered them, it would be best not to use their weapons except in self-defense. If the natives’ good will could be gained, it would not only help them but be of benefit to Professor Bigelow also.

All the remainder of that afternoon the youths tramped on up the trail, hoping to burst at last upon the river. They were tired and downhearted when finally they stopped by a small spring of cool water. Experience had taught them that in the great majority of cases these jungle springs were ideal drinking places and that only a very few were poisoned. So they drank freely of the refreshing liquid and felt much better for it.

“Better stop here for the night, hadn’t we?” asked Bob, taking in the surrounding country.

“Yes,” his friend replied. “There’s a good place to sleep,” pointing to a large hollow in the ground.

A little later darkness fell suddenly, and with it came the usual chill of the atmosphere. Joe had some matches in a small waterproof box, and he took them out and ignited the dry branches of an uprooted tree. The fire blazed lively up into the black reaches of the jungle, giving off heat that was welcomed by the two chums as they sat close together.

Before retiring, they took account of their weapons and ammunition. Joe’s rifle was the only firearm in their possession, but both boys had a large supply of cartridges that should last a long time. With cautious use they might make them satisfy their needs for several days. But after that? Still there was no use worrying about the future. They could let it take care of itself. At present they were safe.

“I’ll take the first guard,” said Bob, half an hour later. “You turn in and get several hours’ sleep. I’ll call you when the night’s half over.”

Joe grudgingly consented. He had intended to stand watch first.

Bob heaped the fire up high and had a good supply of fuel ready to keep it blazing constantly.

But when ten minutes had passed he smothered it down to half the size it had been. It was not wise to keep it too high, for though it was a sure protection from wild animals, it might attract the attention of hostile Indians.

“Have to prevent that at any cost,” the young man thought.

Bob sat moodily fingering his rifle, gazing into the dark depths of the jungle. From afar came a terrorizing howl of some beast that had fallen victim of a stronger enemy. Shortly later there came another howl of different origin. Then another, another, until the whole jungle rang with fiendish cries.

It was enough to frighten anyone, and Bob stared rather fearfully into the surrounding forest, wondering what tragedies were going on at that moment.

“Probably scores of creatures being killed,” he thought, shifting uneasily.

Nothing happened throughout his watch, and he at last moved over and tapped Joe on the back. The latter jumped to his feet as if shot, and gazed fearfully about, as if expecting to see a band of cannibals rush in on them. But a moment later he smiled sheepishly.

“Guess I was dreaming,” he said, taking his position on a log.

Bob readily sympathized with his chum, for the day had been a strenuous one, and their endurance had been taxed severely.

“We’ll surely find a way out tomorrow,” Bob said, curling up in the hollow.

“Hope so,” was the reply.

Joe’s watch was also devoid of incident, and late the next morning he called the other youth from his slumber.

They were obliged to begin the day without any breakfast, although they were extremely hungry. They could have shot some small animal, but Bob thought it wise to wait until noon.

“By that time,” he said hopefully, “maybe we’ll have found the river—or something else.”

They followed the same trail until Joe stopped and looked about.

“We’re not getting any place as things are,” he said. “Seems to me the river should be over in that direction.”

“I think so too,” agreed Bob. “There should be plenty of branch paths that would take us over there.”

They found one before another five minutes had passed, and turned onto its narrow surface.

“The world’s greatest jungle,” mused Bob, shaking his head.

“Sure is a whopper,” the other agreed. “Wonderful. I had no idea it would have such a wide variety of plants, and that it could be so dense.”

All that morning the boys spent in vainly searching for the river. The trail that they had turned onto continued, but where it would lead to they did not know. It might have gradually circled several miles out of the way.

During that desperate search the chums saw a large number of all types of wild animals, although none happened to be dangerous. Monkeys crowded thickly down to the lowest boughs, small gnawing creatures darted across the path, brightly colored birds flew swiftly overhead. Occasionally the boys could get a glimpse of a snake slinking through the underbrush. It was a wonderful menagerie and could have been enjoyed to the full had they not been in such a terrible plight.

“Do you know,” remarked Bob, his eyes on a small creature, “I believe these animals are used to seeing people.”

Joe looked around inquiringly.

“Now take that small furred creature that just passed,” Bob continued. “Did you notice how wary it seemed? One glance at us was enough to send it running back at full speed. They never did that before. Now here’s what I think: we’re in a country inhabited either by rubber gatherers or Indians. Why rubber gatherers would be so far from civilization I don’t know, unless——”

“I don’t think they would be,” interrupted Joe. “We didn’t come across any boat that they might have come in. And of course they wouldn’t have come all these hundreds of miles by land.”

“Then it’s Indians. Savages, cannibals, maybe, for all we know. It’s their bows and arrows that have scared these wild animals out of their wits.”

The youths knew not what to make of the situation. There could easily be Indians in this region, for Professor Bigelow was almost sure they were near the strange savage tribe that Otari told about. But how the natives would treat these two lone whites was a mystery. If there should be a battle the youths knew that their rifle could be relied upon only as long as the supply of cartridges lasted. Then they would be compelled to surrender.

“I have a plan,” stated Joe, several minutes later. “If anything should happen that we are discovered by savages, it might be best to act extremely exhausted, as if we couldn’t stand up a minute longer. We could even fall in our tracks before they quite get sight of us. The chances are they would sympathize with us and take us into their village.”

“Then what?”

“We could gain their friendship and have them lead us to the river.”

“Fine!” cried Bob Holton, his hope renewed. “Takes you to think of some plan to get us out of danger. Most likely we could carry it out, for these savages are only grown children when it comes to catching on to anything unusual. But we’d have to be very careful and keep a close watch for any treachery.”

Along toward noon the youths began to look for game. They were by now furiously hungry and felt as if they could devour almost any creature that would fall at the report of their rifle.

They did not have to wait long before a large duck-like bird flew over and perched on a tree bough, not twenty feet away. Joe handed his rifle to his chum.

“Take a shot at it,” urged Joe. “We may not see another chance as good.”

Bob aimed carefully and fired just as the bird prepared to take flight. A moment later feathers flew and the creature fluttered to the ground.

“Hurrah!” cried Joe. “Now we eat!”

A fire was built of dead wood in the vicinity, and the young hunters’ quarry was placed over the flames to bake. Before long a delicious odor filled the clearing, and the youths prepared a feast fit for a king.

“Roast duck! Think of that!” cried Joe.

The bird tasted good, despite the fact that it was rather tough. Bob and Joe ate heartily, until only a small portion was left. Then they stretched themselves on the soft grass for a short rest.

“I feel like getting some sleep,” remarked Joe. “But of course——”

He stopped suddenly and strained his ears to listen.

Bob looked inquiringly but remained quiet.

A moment later there came a long, weird chant that cut through the thin jungle air with remarkable clearness. It was repeated several times, always nearer. Never before had the youths heard anything like it, and they were intensely bewildered.

Bob looked inquiringly at his friend, but the latter could give no explanation.

“Beyond me,” he muttered.

Again the cry came, and then the boys jumped to their feet in horror.

“Savages!” cried Bob excitedly. “Indians—wild Indians. They’re coming this way!”