“LOOK here, Joe. There’s something stirring. I know the signs. Our dads wouldn’t keep together constantly, studying maps and reading books and making frequent trips to the museum, for nothing. It——”

“You’re right, Bob. They certainly must have something important in mind. And I have an idea as to what it is.”

“Another expedition into the unknown,” cut in Bob Holton, in tones that implied certainty.

“But where, do you suppose?” asked Joe Lewis, his brown eyes sparkling with interest.

“More than I know,” the other youth replied. “Could be any place. But wherever it is, I’ll bet they’ve been there before. They just travel from one end of this little old world to another in search of birds and reptiles and animals, and they always find them.”

“And always will,” added Joe with strong conviction. “Why,” he went on, becoming even more absorbed, “do you remember the time they went to Africa in search of a white rhinoceros?”

“Yes. Looked high and low for several months, and finally got one after all hopes had been abandoned. Oh, it takes them to do it. Just let the curator mention the things wanted, and if it’s at all possible, our dads will get them. All specimens are alike to——”

He was interrupted by the sound of footsteps from the side of the house and turned to see who the person might be. While he is looking expectantly, it might be well to tell who the boys were, and what had been their experiences up to the time this story opens.

Bob was a big fellow, strong and muscular, and endowed with the ability to do the right thing at the right time. He was one of the star players on the high school football team. Everyone liked him—he was so straightforward and sympathizing and trustworthy.

Joe was of medium size, with almost black eyes and a naturally dark complexion. He was lighter and less robust than his friend, but was possessed of fierce courage and bravery. He never started a thing without finishing it.

Mr. Holton and Mr. Lewis, fathers of the youths, were noted naturalists and collectors of specimens for museums and zoos. They had been nearly everywhere and always welcomed any hint that might start them on a new trip into the unknown. The two men had met several years before at a convention of scientists, and took a great liking to each other. As they both lived in Washington, D. C., they agreed to work together in behalf of a large museum, and Mr. Lewis made an attempt to purchase the residence next to that of his friend. He was at last successful in acquiring it, and then began the warm friendship between the two youths, Bob and Joe.

The boys were together much of their time and got along excellently, following in their fathers’ footsteps as much as possible by taking hikes into the woods to study nature. Fresh with the vigor of youth, they were having a grand time together, but would have had a still greater one had they been permitted to accompany the men on the various scientific expeditions.

“You’re only freshmen,” Mr. Holton had told them, about three years before. “Wait till you’re juniors or seniors, and then perhaps we will consider taking you along.”

Now the boys were in their senior year, or would be when school opened the coming fall, and were eagerly anticipating the future.

“If they’d only make a trip this summer,” said Joe, shortly after school had closed. “Then we might——”

Let us return to the boys, as they cast glances at the side of the house. The sound of footsteps grew louder, and the next moment Bob’s father came into view.

“Hello, Dad.”

“Hello, Mr. Holton.”

The naturalist returned the greetings and then made his way to a porch seat. Several moments he spent in lighting a cigar. Then he turned to the youths.

“What’s all this praise you’ve been giving Mr. Lewis and me for our scientific work?” he asked, trying hard to suppress a smile.

The young men grinned. They had not suspected this.

“You got it right,” returned Joe. “You two have done as much for the museum as anyone else in this old U. S. And that’s as straight as a lion’s tail when he’s about to charge.”

Mr. Holton laughed unbelievingly.

“I know your game,” he chuckled. “You’re paving the way to accompany us on that Brazilian trip we’re about to take. Right?”

Bob and Joe jumped to their feet in wild excitement. A trip to Brazil! Think of that! Then their supposition was correct. Something was stirring after all.

Mr. Holton guessed their thoughts and broke the short period of suspense.

“It’s an expedition to the jungles of the Amazon,” he explained, as the boys seated themselves and listened with breathless interest. “Going to get specimens of fauna for the museum. In addition, we wish to make a study of several wild Indian tribes there. It’s a trip I’ve always wished to take, but, strange to say, I’ve never had the opportunity. You boys probably know that this region is one of the least-known on the face of the globe. It has the world’s heaviest forests, some of the most savage of people, and a wide variety of birds and beasts.”

“Great!” blurted out Joe in a strange, animated tone. “How wonderful it would be! Away out in the wildest of Brazilian wilds, seeing strange and astonishing things—things that only a very few have the opportunity of seeing.”

“It’s my idea of adventure,” declared Bob, taking up where his friend had left off. “Why can’t you arrange to take us with you?”

The scientist eyed the young men intently with an expression of sympathy.

“Then you want to go that badly?” he asked, and then his eyes fell. He had been young himself once. How often had he visualized this very mission! How many times had he tramped through the heavy Western woods, imagining himself in a great tropical forest, with its mysteries, thrills, and tragedies! If those longings could only have been satisfied when they were strongest!

For over a minute Mr. Holton stared thoughtfully at the floor. Then, with twinkling eyes, he glanced up at the boys.

“What would you give to go with us?” he asked, his face brightening.

“What!” cried Bob, with a look that combined delight with bewilderment. “You mean that we can go?”

“Not exactly,” was the reply. “I just asked you what you’d give to go.”

“Everything!” blurted out Joe. “Everything we’ve got—and then some. Oh, do take us, Mr. Holton,” he went on more pleadingly. “We’re old enough by now to take care of ourselves.”

“I’d like to have you,” the naturalist said. “And so would your father. But your mothers——” Here he stopped. It was unnecessary to continue. The youths understood.

“But I’m sure they’ll consent,” Bob said, with a certainty that he was far from feeling. “Especially if they know you are willing to have us.”

“Of course there’s a possibility,” the man assured them. “But I wouldn’t be too sure of it. You know how they are. Unwilling to have their sons take any unnecessary risks. Well, perhaps they’re right,” he went on, tapping the chair thoughtfully. “Perhaps it isn’t best to tax good fortune too much. You boys are young and have a great future before you. What if anything should happen——”

“But, Dad,” Bob pleaded, “nothing will happen. We’d be with you and Mr. Lewis—and anyone else who would be along. Nothing has happened to you so far. You’ve always come back O.K.”

“We’ve had some narrow escapes, though,” with a shaking of the head. “Fever, wild beasts, savages, hurricanes—there’s no limit to the number of tragedies that may befall an expedition into the unknown. But then,” his tones became more lively, “you boys want to go with us regardless of these dangers, and if I must say so, I believe you’d make a good showing. I’ll talk the matter over with Mr. Lewis and your mothers and let you know later how things look.”

“Fine!” cried Bob, overwhelmed with joy. “Now tell us some more about this mission. What section of Amazonia do you intend to explore?”

“The lower middle,” was the response. “We intend to follow the Amazon to the PurÚs River, where we’ll branch off and travel by native canoes for approximately five hundred miles.”

Joe gave a long whistle.

“Five hundred miles by canoe!” he gasped, almost unbelievingly. “Seems almost impossible. How can you take food enough along?”

“Does seem sort of absurd. But we’ll manage it. And we expect to live on game and fish to a certain extent. Everything will have to be timed to a dot. We won’t dare stay any longer than our food supply lasts. When that begins to get low, back to civilization we’ll go.”

“How long do you expect to be gone?” Bob asked.

“We—ll, perhaps three or four months. We want to get as much done as possible. You see,” he explained, “as I said before, our stay is limited to the supply of provisions we have with us. If it were possible to carry enough, I would like to spend at least six months there. What a wonderful opportunity to study primitive man in his everyday life.”

“Should think it would be rather dangerous,” remarked Joe. “He might object and study you instead. Headhunters, I mean.”

“It’s a chance we have to take,” was the reply. “But after all, if we treat them kindly there is little danger. Human nature is much the same all over the globe.”

“I’ll trust you to come out all right,” Bob said.

“We hope to,” the scientist returned. “And we also hope to add greatly to the world’s knowledge of Brazil and its animal inhabitants.”

“At present that isn’t very much, is it?” Joe asked.

“You can’t exactly say that,” Mr. Holton answered, “for a large amount is known about different sections that have been more or less frequented by civilized man. But when you refer to the deeper, more inaccessible regions, then it’s different. Of course there have been numerous expeditions sent out to explore these unknown sections, but even now there is a large and interesting field open to the scientist.”

“Well,” said Bob, after a short silence, “I only hope that Joe and I may go with you.”

“We’ll see about it,” his father replied. “But I can assure you that consent from your mothers will not come without considerable—— Well! Look who’s here. Come on the porch and sit down, Ben.” He referred to Joe’s father, Mr. Lewis, who, as usual, was to be his intimate companion during their stay in Brazil.

Mr. Lewis was a man of medium height, with sparkling blue eyes and a complexion that was extremely bronzed.

“Hello, friends,” he greeted, seating himself and wiping the perspiration from his brow. “I suppose,” he said to Mr. Holton, “you’ve been telling the boys about our coming expedition to South America. Right?”

“Right!” echoed Bob. “And not only that, but Joe and I are going with you.”

“What’s that!” Mr. Lewis cried in surprise.

“Yes,” Bob’s father returned, “they’ve put in their request to be a part of the expedition. What do you think of it?”

“Well—a—I hardly know. How do you think their mothers will look at it?”

Mr. Holton shook his head.

“Impossible to say,” he answered. “But we can all guess. Still, if we see fit to take the boys along, we can put the matter before them. They may consent after considerable pleading.”

“Hurrah!” cried Joe, in tones of gratitude. “And I’m sure——”

He stopped suddenly and sniffed the air sharply.

“There’s something burning,” he said quietly, and then moved around the house.

The next instant he was back, pale-faced and panic-stricken.

“Our garage is on fire!” he cried. “It’s all ablaze!”