With his green collecting box and his butterfly net the naturalist disappeared along a path that led through the forest.
"I suppose he'll come back with a blue-nosed baboon or a flat-headed gila monster," said Ned. "He does find the queerest things."
It was almost an hour later, when the boys were wondering what had become of the naturalist, that they heard faint shouts in the direction he had taken.
"Hurry, boys!" the professor's voice called. "Hurry! Help! help! I'm caught!"
"He's in trouble again!" exclaimed Ned. "We must go to his rescue!"
"Have you got your revolver?" asked Jerry, as Ned was about to rush away.
"Better get it. I'll take a rifle along. Bob, you bring the rope. No telling what has happened, and we may need all three."
With rifle, revolver and rope the three boys rushed into the forest to the rescue of their friend. They could hear his shouts more plainly now.
"Hurry or he'll kill me!" cried the professor.
Running at top speed the boys emerged into a sort of clearing. There they saw a sight that filled them with terror.
Professor Snodgrass was standing underneath a tree, from one of the lower branches of which a big snake had dropped its sinuous folds about him. The reptile was slowly winding its coils about the unfortunate man, tightening and tightening them. Its ugly head was within a few feet of the professor's face, and the man was striking at the snake with the butterfly net.
"We're coming! We'll save you!" shouted Jerry.
The boy started to run close to the naturalist, intending to get near enough to fire at the snake's head without danger of hitting the professor.
"Look out!" yelled Bob, pointing to the ground in front of the tree. "There's another of the reptiles!"
As he spoke a second snake reared its head from the grass, right in the path Jerry would have taken. Bob had warned him just in time.
Jerry dropped to one knee. He took quick but careful aim at the snake on the ground and fired. The reptile thrashed about in a death struggle, for the bullet had crashed through its head.
He ran in close to the reptile that was slowly crushing the professor to death. The unfortunate naturalist could no longer cry for help, so weak was he.
Jerry placed the muzzle of the rifle close to the snake's head, and pulled the trigger. The ugly folds relaxed, the long, sinuous body straightened out and the professor would have fallen had not Jerry, dropping his gun, caught him. The other boys came to his aid, and they carried the naturalist to one side and placed him on the grass.