The land around the Amazon River is called “Selvas”—which means “woods.” It is not only woods but jungles and swamps, and it is very wild, hot, damp, and unhealthful. It is so hot and damp that everything grows big and thick and fast—so big that water lilies grow leaves as big as the top of a dining-room table; so thick that man can hardly make his way through; and as fast as Jack the Giant Killer’s beanstalk.

There are many animals but few men in the Selvas, and the men are mostly Indians. There are many monkeys, the kind organ-grinders use. There are parrots, which sailors catch and teach to speak and bring back home. There are butterflies and moths of great size and beautiful colors that a boy would love to have for his collection. There are huge snakes called boa-constrictors, that look like heavy vines hanging from branches to fool other animals which they catch, coil around, and hug to death, then swallow whole and go to sleep for a week or month while the meal is being digested. There are animals that hang from trees by their toes like a boy on a trapeze, and even sleep upside down; lazy, sleepy animals that never seem to be awake, and move, when they do move, so slothfully they are called “sloths.” There are animals like dragons, called “iguanas.” There are huge bullfrogs whose croaking sounds like the roar of lions. And there are mosquitos, the country mosquitos that give you malaria. You may wonder why any one goes to the Selvas at all. They go a-hunting for animals for museums and zoos, but the chief thing they go hunting for is the juice or sap of a tree that grows wild in the Selvas.

White people found the Amazon Indians playing with balls that bounced and bounded. They had seen nothing of the sort before. These balls, they found out, were made of the sap of a tree. That gave the white man the idea that this sap might be used to make balls for white children and white men to play with—babies’ balls, tennis-balls, golf-balls. Then they found that lumps of it would rub out—so they called it rubber—and that they could make rubber erasers, automobile tires, rubber bands, and rubber boots of it. Soft rubber and hard rubber and pully rubber and springy rubber are all made from the sap of the rubber-tree by treating it in different ways as a cook makes taffy and gum-drops and caramels by cooking sugar in different ways.