To produce a _pelle_, the big black ball which may be seen in Pará and Manáos on the wharves, in warehouses, on the pavements, whole or sliced in halves with their creamy hearts displayed, or floating down the tributary rivers on rafts, the _seringueiro_ has to work for about a month. Each day’s collection of latex is coagulated on top of the previous rubber until the ball is made to what the _seringueiro_ thinks is a convenient size. Day after day, only interrupted by sickness, he labours in the sweltering forest at this toil, eating food of very limited variety, without exchanging a word, perhaps, with another human being for weeks at a time; each _seringal_ is supposed to be under inspection, to avoid maltreatment of the trees, but as a rule this supervision is a fiction. Small wonder that when the collector at last leaves the _seringal_, and takes his rubber to Manáos, he spends a few riotous days, limited by the amount of his money balance remaining after the debt has been paid to the _aviador_. The aviador it is who also buys the pelles and in the busy season when rubber begins to come in, these stores present a curious sight. Sometimes the _seringueiro_, in good years, saves money; he may buy a seringal or a little store of his own; a few fortunes have thus been made from the collector class, but they are rather the exceptions that prove the rule. These conditions, under which a nominally independent collector works in a rented _estrada_ and sells his rubber to the store-keeper to whom he is in debt—and who is often also the owner of the _seringal_—are general as regards the collection of the latex of the “black” rubber trees of the upper Amazon. This is the origin of the _fina_ class of rubber, with _sernamby_ or scrap as a kind of by-product, result of carelessness; the _fina_, however, is usually at least eighty per cent of a good workman’s product, and this is the rubber which, with _caucho_, has made Manáos. _Caucho_ is rubber produced from the milk of _castilloa elastica_, growing in profusion along the banks of the Rio Branco, tributary of the Negro, in North Amazonia and on many streams of Peruvian origin; the industry connected with this tree is really independent, the result of individual searchings for trees. Parties go up these rivers, hunt in the bordering woods for the _castilloa_, straightway cut it down and bleed it for the last drop of latex, and go on their way. Down near the mouth of the Amazon, where the “white” rubber trees are most commonly found, it is not unusual for collectors to own sections of forest with their little homes at its edge; they, too, are almost independent—of everything except the industrial conditions upon the Amazon, and the rubber prices fixed far away in London or New York.