These sand banks are considered to be the richest turtle grounds in the basin of the Upper Amazon.
On the evening of the 29th of July they were securely moored off the island of Catua, so as to pass the night, which promised to be dark.
On this island, as soon as the sun rose above the horizon, there appeared a party of Muras Indians, the remains of that ancient and powerful tribe, which formerly occupied more than a hundred leagues of the river bank between the Teffe and the Madeira.
These Indians went and came, watching the raft, which remained stationary.

There were about a hundred of them armed with blow-tubes formed of a reed peculiar to these parts, and which is strengthened outside by the stem of a dwarf palm from which the pith has been extracted.
Joam Garral quitted for an instant the work which took up all his time, to warn his people to keep a good guard and not to provoke these Indians.
In truth the sides were not well matched.

The Muras are remarkably clever at sending through their blow-tubes arrows which cause incurable wounds, even at a range of three hundred paces.
These arrows, made of the leaf of the _"coucourite"_ palm, are feathered with cotton, and nine or ten inches long, with a point like a needle, and poisoned with _"curare."_ Curare, or _"wourah,"_ the liquor "which kills in a whisper," as the Indians say, is prepared from the sap of one of the euphorbiaceae and the juice of a bulbous strychnos, not to mention the paste of venomous ants and poisonous serpent fangs which they mix with it.
"It is indeed a terrible poison," said Manoel.

"It attacks at once those nerves by which the movements are subordinated to the will.

But the heart is not touched, and it does not cease to beat until the extinction of the vital functions, and besides no antidote is known to the poison, which commences by numbness of the limbs." Very fortunately, these Muras made no hostile demonstrations, although they entertain a profound hatred toward the whites.