The boys had the edge taken off their rash ardour long before, but that sinister warning from the forest in the shape of the arrow had driven home again the lesson that it was necessary to be always on guard.
The forest, in its silence and in its gloom, was menacing.

They glanced up the river.

It stretched away like an avenue cut out of a solid mass of vegetation, and all the length to the spot where the banks seemed to run together, as if the river had ended, there was no sign of living thing.
Suddenly an animal darted across the clearing and crouched behind Muata.

It was the jackal, the hair on its neck erect, and its body quivering with fear, or excitement.

Then a branch snapped with a startling report, there was a violent shaking of leaves, a short bark-like roar, and then a noise of shaking gradually decreasing.
Muata had fallen back to the river's brink at the roar, but now he turned his attention once more to the clearing.
"What was that ?" "Man-monkey," he said quietly.
"Gorilla! By Jove!" and the boys stared into the forest, and then at each other.