Among the other more important trees which produce rubber may be mentioned the Siphonia brevifoglia, the Siphonia brasiliensis, Siphonia rhytidocarpa, and the Siphonia lutea, all found chiefly in the State of Para. In other parts of Brazil grow the Ficus anthelmintica, the Ficus doliaria (or gameilleira), the Ficus elastica, Ficus indica, Ficus religiosa, Ficus radula, Ficus elliptica, Ficus prinoides, the Plumeria phagedenica, the Plumeria drastica, the Sorveira or Collophora utilis, and the Mangabeira or Harncornia speciosa.
At present we shall be chiefly interested in the seringueira (Siphonia elastica).
The collection of the latex from the seringueira and the subsequent process of coagulation were simple enough. A seringueiro, or rubber-collector, started from his hut early every morning carrying with him a small steel axe or pick, the head of which was 3 in. long and shaped like a bird's beak; a tin bucket, and some barro—soft clay which had been soaked in water. He walked along the estrada or track which he had cleared for himself, leading from one rubber tree to the next. There may be twenty, thirty, fifty or more rubber trees that have been tapped on one estrada, according to the district and the activity of the seringueiro. In the case of a new tree a collar of the fibre of burity palm was in the first instance nailed with pegs of hard wood round the stem, not horizontally, but at an angle: sometimes, when necessary, in a spiral. In other cases a similar band of clay was made to encircle the tree. These collars served as channels, compelling the latex, as it exuded from cuts made in the tree, to flow into a small tin cup suspended at the lowest point of the collar. The incisions were never made lower than 2 or 3 ft. from the ground. They must not penetrate deeper than the entire thickness of the bark of the tree, and they must on no account touch or wound the actual wood, or the tree would suffer greatly—even die. In some regions the incisions were made longitudinally, in others transversely. The operation was repeated by the seringueiro each time on every rubber tree as he went along the estrada, the latex flowing freely enough into the tin cup after each fresh incision had been made.
The seringueiro thus tapped each tree on his way out along the estrada, which in some cases may be several miles long; in other cases, where rubber trees were plentiful, only a few hundred yards in length. On his return journey the seringueiro emptied each small tin cup—by that time filled with latex—into the large bucket which invariably accompanied him on his daily round. Rubber-trees possess in a way at least one characteristic of cows. The more milk or latex one judiciously extracts from them, the more they give, up to a certain point. But, indeed, such a thing is known as exhausting a tree in a short time. A good seringueiro usually gives the trees a rest from the time they are in bloom until the fruit is mature. In some regions even a much longer respite is given to the trees—generally during the entire rainy season. In some localities, too, in order to let the latex flow more freely, a vertical incision is made above and meeting a horizontal one. At intervals oblique incisions are cut next to the vertical ones, but in Matto Grosso I never saw that complicated system of incisions adopted—only vertical incisions parallel to one another at a distance of 0·25 m. (9⅞ in.) being made there, and in rows one above another. Some of the trees had actually hundreds of those cuts—many, of course, healed. Each cut only exudes latex for a comparatively short time, merely an hour or so.
During the first month after a tree is tapped, the supply of latex is generally plentiful; the second month it gives less; less still the third month. On an average twenty trees give about one litre of latex a day. Three litres of latex are necessary in order to obtain one litre of rubber. At the head-waters of the Arinos River 600 trees gave from 30 to 35 arobas (450 to 525 kils.) of fine rubber in the first month, and about 20 arobas (300 kils.) of sarnambé (second quality with impurities). One aroba is 15 kils.
The latex of the seringueira in the Arinos region was of a beautiful white, quite liquid, and with a pungent, almost sickening, odour. When a new tree was tapped, the lower towards the ground the incisions were made the better. If after considerable tapping the tree did not yield much, it was advisable to incise the tree higher up. In that region the trees exuded latex more abundantly when they began to have new leaves in October. Late in the dry season the latex flowed less freely. When the weather was windy all the latex seemed to contract to the summit of the trees and hardly flowed at all from the incisions. When it rained, on the contrary, it flowed freely, but was spoilt by being mixed with water; so that a good seringueiro must know well not only where and how, but also when to tap the trees, in order to get good results.
Balls of Rubber outside a Seringueiro's Hut.
