FORESTS—SNAKES—RIO NEGRO. 963 
and consists of muriate of potash and soda, caustic 
lime, and other ingredients. The Indians dissolve a 
few grains in water, which they drop on their food. 
On the 5th May the travellers set off on foot to fol- 
low their canoe. They had to ford numerous streams, 
the passage of which was somewhat dangerous on 
account of the number of snakes in the marshes. 
After passing through dense forests of lofty trees, 
among which they noted several new species of coffee 
and other plants, they arrived toward evening at a 
small farm on the Pimichin, where they passed the 
night in a deserted hut, not without apprehension of 
being bitten by serpents, as they were obliged to lie 
on the floor. Before they took possession of this shed 
their attendants killed two great Mapanare snakes, 
and in the morning a large viper was found beneath 
the jaguar-skin on which one of them had slept. 
This species of serpent is white on the belly, spot- 
ted with brown and black on the back, and grows © 
to the length of four or five feet. Humboldt re- 
marks, that if vipers and rattlesnakes had such a 
disposition for offence as is usually supposed, the 
human race could not have resisted them in some 
parts of America. 
Embarking at sunrise they proceeded down the 
Pimichin, which is celebrated for the number of its 
windings. It is navigable during the whole year, 
and has only one rapid. In four hours and a half 
they entered the Rio Negro. “‘ The morning,” says 
Humboldt, “‘ was cool and beautiful ; we had been 
confined thirty-six days in a narrow canoe, so un- 
steady that it would have been overset by any one 
rising imprudently from his seat, without warning 
the rowers to preserve its balance by leaning to the 
