The boys prepared to follow, as the doctor led off; but Harry directed a malicious glance at his companion, which seemed to say plainly, "Look out, and see if he doesn't go in."
But Harry felt disappointed and ill-used, as well as wet and muddy about the legs, for the doctor strode off steadily for about twenty yards, the boys following over perfectly firm ground.
"You should pick your way in a place like this, my lads. It only needs—"
Care, the doctor was about to say, but he did not; for all at once, to Harry's intense delight, his leader uttered a sharp ejaculation, and, throwing himself flat on the ground, began to roll over and over, with his gun held upright against his breast, till he was close to the boys' feet, where he sat up, drew the stout hunting-knife he wore at his breast, and began to scrape the mud off one leg.
"Was it soft there, sir?" said Harry, with mock seriousness.
"Soft!" cried the doctor. "Oh, you're laughing at me, eh? Well, I'm fair game, I must own. Here, step back! quick! both of you. We're sinking."
It was quite true, for there was a bubbling, hissing, and gurgling sound arising from among the grassy growth, and the black water began to ooze up among the stems, so that as the boys ran back it splashed up, and the doctor followed, none too soon.
"Why, the whole place is a marsh," he said, looking back as soon as the ground felt more solid. "It is just as if the water of the river spread right up to the jungle and this part had become covered with weeds and plants till they were matted together and looked like a meadow."
"But," cried Harry, "I want to know how the elephants managed."
"There must be a sort of causeway of firm ground somewhere out in the middle there," replied the doctor. "I daresay we should find it so if we went back with the boat to where the great creatures came out of the water."