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Commodore Directory 03
Page 06
Had we not constructed that raft--had we not been on board at that moment--we should have missed the expedition and certainly should have died. Had we been following the bank of the river on foot, we never could have seen the boats nor heard them, as the banks were extremely high, and it was never possible to keep close to the stream when marching in the forest; we always had to keep some hundred metres or so from the water in order to avoid the thick vegetation on the edge of the stream. In fact, Benedicto, who was walking in the forest along the stream, had gone past the boats and had neither heard nor seen them. When we shouted out to him he was already a long distance off, a boat sent out to him by Dom Pedro Nunes having to travel nearly 800 m. before it could get up to him and bring him back.
Somewhat higher than the fish in the scale of life is the frog. Although he begins life as a fish, and in the tadpole state breathes by gills, he soon discards the water-diluted air of the pond, and with perfect lungs boldly inhales the pure air of the upper world. His life as a tadpole, although so fish-like, is much inferior to true fish life: for though the fish has not the perfect lung, he has a modification of it which he fills with air, not for breathing purposes, but as an air-sac to make him float like a bubble in the water. Will he rise to the surface? he inflates the air-bladder. Will he sink to the bottom? he compresses the air-bladder. But in the frog the air-bladder changes into the lungs, and is never the delicate balloon which floats the fish in aqueous space. When the frog's lungs are perfected, his gills close, and he forever abandons fish-life, though being a cold-blooded creature he needs comparatively little air, and delights to return to his childhood's home in the bottom of the pond. But although he can stay under water for a long time, he is obliged to hold his breath while there, and when he would breathe must come to the surface to do so. It is possible to drown him by holding him under water.
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