somewhere far up in Bolivian territory. No settlements are to be found
up there; a few _seringales_ from seventy-five to a hundred miles
apart constitute the only human habitations in this large area. So
wild and desolate is this river that its length and course are only
vaguely indicated even on the best Brazilian maps. It is popularly
supposed that the Itecoahy takes its actual rise about two weeks'
journey from its nominal head in an absolutely unexplored region.

I found the life very monotonous in Remate de Males, especially when
the river began to go down. This meant the almost complete ending of
communication with the outer world; news from home reached me seldom
and there was no relief from the isolation. In addition, the various
torments of the region are worse at this season. Sitting beside the
muddy banks of the Itecoahy at sunset, when the vapours arose from the
immense swamps and the sky was coloured in fantastical designs across
the western horizon, was the only relief from the sweltering heat of
the day, for a brief time before the night and its tortures began. Soon
the chorus of a million frogs would start. At first is heard only the
croaking of a few; then gradually more and more add their music until
a loud penetrating throb makes the still, vapour-laden atmosphere
vibrate. The sound reminded me strikingly of that which is heard when
pneumatic hammers are driving home rivets through steel beams. There
were other frogs whose louder and deeper-pitched tones could be
distinguished through the main nocturnal song. These seemed always
to be grumbling something about "_Rubberboots--Rubberboots_."

By-and-bye one would get used to the sound and it would lose
attention. The water in the river floated slowly on its long journey
towards the ocean, almost 2500 miles away. Large dolphins sometimes
came to the surface, saluting the calm evening with a loud snort,