THE HEVEA RUBBER TREE IN THE AMAZON VALLEY H 
a big machete (tercado in Portuguese) in his hand and the indis- 
pensable Winchester .44 over his shoulder he enters the jungle and 
searches out the rubber trees. As he locates them he connects them 
by a trail cut through the undergrowth, and this trail connecting the 
rubber trees is his estrada. Estradas vary in the number of trees which 
they contain, from 50 to 300, depending on the conditions and the 
men who lay them out. 
Generally a seringueiro will lay out two or three estradas extending 
in different directions from his dwelling, and these are afterwards 
tapped in rotation. After the trees in the estradas are located, some 
further work is necessary to clean the trails more thoroughly, to bridge 
streams with poles, and the like. Then the seringueiro is ready to 
begin tapping. Of course, if old estradas are to be worked all this is 
unnecessary; he has only to move into the house built by his prede- 
cessor, cut the recent growth from the estrada, and repair a few 
bridges. 
Although a seringueiro may thus establish a collecting ground of his 
own at some distance from any of his fellows, it is more usual for a 
group of seringueiros to enter a region together and lay out estradas 
near each other. 
Such a group of estradas on a rubber property is called a seringal. 
Each seringal has a barracao, or large warehouse and dwelling com- 
bined, where the agent of the man or company owning or leasing the 
rubber property lives. In the barracao a store of food and supplies 
for the seringueiros is kept. These commodities are advanced to 
the seringueiros as they need them and are charged against the value 
of the rubber which they bring to the barracao from time to time. 
The plan of a seringal with its estradas may be seen in Pearson's 
book {32, p. 63). The map of an estrada in Matte- Grosso studied in 
detail by the writer is shown as Figure 3. 
Tapping is begun by the seringueiro in the early morning. In- 
cisions are made in the bark of the rubber tree with a small ax, called 
a machadinho. The purpose of these incisions is to open the latex 
vessels which extend through the cortex of the tree, so that the latex, 
or "milk," may flow out. The cuts are made in a slanting direction, 
so that the latex flows from the upper end of the cut to the lower, 
where a cup is placed to receive it. This cup is made of light-weight 
tin plate and is affixed to the tree by thrusting the sharp edge of the 
brim into the bark. 
Several incisions are made at equal intervals around the tree and 
cups placed beneath them, when the seringueiro hurries on to the 
next tree. So he continues until the whole estrada is tapped. Usually 
he has finished tapping by 9 o'clock. Early tapping has been found to 
give the highest yields, as the flow of latex decreases considerably as 
the temperature rises, partly, perhaps, because of the effect of the 
heat in coagulating the rubber on the cuts and stopping the flow and 
partly because of the increased transpiration of the tree, which may 
lower the pressure in the latex tubes and so diminish the flow. 
When the seringueiro judges that the flow of latex has ceased, he 
begins to collect the contents of the cups. The latex from each cup 
he pours into a narrow-mouthed tin pail, called a "balde," of about 
2 gallons capacity. When the balde is filled he pours the latex 
from it into a cloth bag which has been thoroughly coated with latex 
and smoked to coagulate the rubber on its surface, so that it is 
