"Well?" said Jack.
"Well, I heard a soft footstep and the crackling of some twigs. I looked round and my bag of specimens had gone. Now which of you boys played that foolish joke on me?"
"I'll give you my word we know nothing about it, professor," declared Tom. "Dick and I have been working all the morning unpacking stuff from the Wondership."
The professor looked at them incredulously.
"That's right," struck in Zeb, "they haven't been out of my sight."
"But—but," stammered the professor, "my dear sir, that bag of specimens didn't walk off, you know. Besides," he added, "I heard a human footfall distinctly."
"It may not have been the boys, though," spoke up Jack seriously.
"Indeed, who else then?" inquired the professor stiffly.
"An unwelcome neighbor," replied Jack. "We are not alone on this island."
"Not alone? What do you mean?" demanded the professor in thunderstruck tones.