"Doesn't sound very healthy," whispered Denbigh with a forced laugh. "I think I'll arm myself with a club."
He wrenched at a stout sapling. Instead of the stem coming out by the roots as he expected, it snapped off short. The fractured part tapered to a chisel edge. The wood was hard and close-grained.
"No, I'll use this as a spear," continued the sub. "It makes a nasty weapon to jab an animal with."
In silence the chums proceeded on their way. It was fair going between the trunks of the palms and mangroves, there being very little undergrowth.
"'Ware mosquitoes," exclaimed O'Hara. "There must be a swamp somewhere about."
A swarm of these pestilential insects were buzzing around their heads, but, possibly owing to the protection afforded by the burnt cork, the mosquitoes did not press home the attack. Fifty yards farther the two men were stopped by a deep morass.
"Edge away to the left," suggested the Irishman. "I think I can hear running water. By Jove! Look at those fireflies. They're simply great."
Denbigh merely grunted. He was in no mood to study the beauties of nature. The marsh meant loss of valuable time.
Half a dozen small deer, disturbed in the act of drinking, came bounding towards them, until, finding themselves confronted by human beings, they stopped abruptly, then tore madly from the newest danger.
"Be careful!" urged Denbigh. "Those creatures have been driven towards us by some animal. Stand by."