Many varieties of the same species of tree belong to the family which is known as “the Heveas,” and several of them are rubber-givers. All rubber obtained from trees of this family has the distinctive name of “Para” in the commercial world. Three qualities of wild Para are sent to market—fine, entrefine or medium, and coarse or negro-head.

Fine Para is best quality rubber made from the richest kinds of Hevea milk. It is cured through and through, whilst the latex is being coagulated, with the smoke of palm-nuts. The nuts most commonly used in the Amazon region are the fruit of the urucuri palm, which flourishes in the forests where the Heveas are found. Various products are turned to account as fuel for curing rubber in other parts of the world, but the results, taken as a whole, have led to a general opinion that the smoke of the palm-nuts used in the Amazon country plays an important part in keeping the rubber of this region first of all rubbers as regards quality; but the secret of this smoke’s special power has not yet been discovered.

Entrefine or medium Para is made from Hevea milk other than the very richest; or it may be the result of best quality milk which has only been indifferently well cured.

Coarse Para, or negro-heads, is uncured or partly cured refuse. When a tree has been tapped, some of the milk in the collecting-cups cakes into a thin crust on the inside of the bowls, and drops fall and congeal on the rim and outer surface. The scraps have to be cleaned off the cups every morning, for new milk loses much of its value if it is allowed to come into contact with dirt or refuse; sometimes they are thrown away, but frequently they are hoarded in a bag which the seringueiro takes with him on his tapping round for this particular purpose. The refuse is well worth saving, for it will fetch quite a good price as negro-heads. But such coarse rubber is not always an extra source of income to the seringueiro. Sometimes he loses considerably by it, for he finds himself, through no fault of his own, with nothing but this poor quality material as the reward for his day’s toil. If it rains hard whilst the trees are being tapped, the latex curdles in the collecting-cups, and the seringueiro has to collect a supply of negro-heads instead of fresh milk. Again, the milk sometimes coagulates much too quickly when it is being cured; the material produced is then negro-heads instead of fine or even medium Para.

In the commercial world Para rubber has many secondary names, which tell from which particular district such or such a supply has been obtained. The chief rubber-producing regions in the Amazon country are:

1. The Brazilian State of Para, in the Lower Amazon Valley, including the islands in the mouth of the river. One very good quality rubber from this region is called “Caviana,” after the island of that name, where it is obtained.

2. The Brazilian State of Amazonas, in the Upper Amazon Valley. Rubber produced in this State is known generally as “up-river” rubber; it is also called “Manaos,” after the great commercial centre of the industry in this region, or “Madeira,” after a tributary of that name which gives access to some of the richest rubber lands in the State.

3. Acre. This is a far interior territory, bordering on Peru and Bolivia. Acre, which is now federated with Brazil, is very famous for its rubber, which, like that of Amazonas, is generally known as “up-river” rubber.

4. The Brazilian State of Matto Grosso, in the Upper Amazon Valley. At present very little of this vast forest-land between Amazonas and Paraguay has been opened up, but, judging by what has already been seen of its dense jungle, the whole State is a treasure-ground of rubber-trees. Most of the rubber now exported from this district is coarse, and sun-cured instead of smoke-cured. It, too, is called “up-river” rubber.

5 and 6. Bolivia and Peru. Both countries export large quantities of rubber, much of which is of excellent quality. The various grades of Bolivian and Peruvian Para are classed collectively as “up-river” rubber; but the different qualities have native names as well, and these are quite popular as trade terms.

The Amazon country furnishes a rubber that is quite distinct from the Para material. It is called “Caucho,” and is obtained from a tree known as the Castilloa Ulei. The biggest exporters are Peru and Bolivia.

There is no system of estradas to simplify the work of the caucho-gatherers. A search-party, largely composed of Indians, sets out to hunt for castilloa trees in parts of the forest that have never before been explored. There is not so much as a track to help them on their journey, nor a clue of any kind to tell them in which direction to cut their way. In order to collect enough caucho to make a success of their trip they will probably have to travel several hundred miles; quite likely they will lose themselves, and have to wander about for months before they happen to strike the right direction towards some isolated village. All their baggage has to be carried by hand or on the back, so only the barest necessities are taken. A large share of each man’s burden consists of provisions; even so, the stores are scanty enough, seeing that no one knows for how long they will have to be eked out, with the help of any game that may be shot.

Every castilloa-tree that is found is felled to the ground, and is then ringed with cuts, which extend the whole length of the trunk, at intervals of about 2 feet. The milk which runs out from these cuts is caught in little bowls. These are either fashioned from leaves, which are folded and sewn together, or they are made from seed-pods—in which case they are called “calabashes”—in the very simple way that you can easily make a cocoanut-shell do duty for a basin or a cup.

The contents of the bowls are poured into a hole in the ground or a scooped-out hollow in the trunk of a fallen tree, and the milk is coagulated with the help of soap, lime, or potash. After a few days the lumps of caucho are pressed together into square blocks, the market name for which is “Peruvian Slab.”

Some of the milk sticks in the cuts and becomes coagulated through exposure to the air. About a fortnight after a tree has been felled the congealed caucho is picked out of the wounds. It comes away in stringlike strips, which are wound into balls. Some of these caucho balls are very roughly made; others are put together in a most pleasing way—the narrow golden strips are prettily interlaced the while they are being wound into a compact, round bundle; in its finished state the ball looks as if it had been fashioned from strips of bamboo by the patient, skilful hands of a Japanese toymaker.