Vol. LXII, No. 2810. 
NEW YORK, DECEMBER 5, 1903. 
$1 PER YEAR. 
THE BOOM IN RUBBER CULTURE. 
How the Rubber Is Gathered and Prepared. 
The consumption of rubber bas enormously increas¬ 
ed of late owing to its extensive use in electrical ap¬ 
pliances, for tires on many forms of road vehicles, and 
in the arts generally. The consequent rapid appre¬ 
ciation in price of the crude article has set on foot a 
multitude of speculative enterprises in the form of 
stock companies for the cultivation of rubber trees in 
Mexico, Central America, Porto Rico 
and the Philippines. These companies 
advertise largely, and issue boom litera¬ 
ture filled with glowing estimates of 
profits to investors, based largely on 
misconception if not actual ignorance of 
the conditions needed for the growth 
and proper development of rubber-pro¬ 
ducing plants. The United States De¬ 
partment of Agriculture has issued in 
Bulletin No. 49, Bureau of Plant Indus¬ 
try, a timely account of experiments to 
date in the culture of the Central 
American rubber trees, which may go 
far to disabuse the minds of those daz¬ 
zled by prospects of illimitable and 
quickly realized profits to be gained in 
rubber planting. 
RUBBER A SCARCE PRODUCT.— 
Many plants growing naturally in tem¬ 
perate and warm climates produce milky 
juices that coagulate on exposure to the 
air or various chemicals, but only the 
latex or milky sap found in the bark 
cells of a few trees or woody climbers 
native to the tropics retains sufficient 
elasticity when hardened to be of com¬ 
mercial value. Rubber appears to be a 
vital secretion of the plant, and floats in 
minute globules in the latex just as the 
globules of butter do in milk until sep¬ 
arated by churning, but is not known to 
be of any special physiological service 
to the plant in which it is produced. 
Rubber trees may be induced to grow 
vigorously under various horticultural 
conditions and yet not produce enough 
rubber to pay for tapping. The whole 
subject of rubber culture is still in the 
early experimental stage, to be worked 
out by patient and costly experiment, 
and is not yet a fit subject for invest¬ 
ment by those looking for summary 
profits. 
AMERICAN RUBBER TREES.—The 
American rubber plants of commercial 
importance belong to two genera of for¬ 
est trees. The most important species 
are Castilla elastica, found throughout 
Central America, northward to tropical 
Mexico, and Hevea Brasiliensis, the Para 
rubber tree, which is almost entirely 
confined to the Amazon Valley. The last 
named is a huge forest tree, the trunk 
attaining a diameter of three or more 
feet, and until lately has been the source 
of most of the rubber imported into the United States. 
But few attempts have been made to cultivate Hevea 
except in British India, where experiments have been 
going on since 1877, with little prospects for commer¬ 
cially profitable results. The culture of Castilla is 
now being exploited to a considerable extent by in¬ 
dividuals and corporations in Central America and 
Mexico. Enough has been done to render it evident 
that the tree can he easily propagated from seeds or 
cuttings, and that it may be made to grow thriftily 
under many conditions not conducive to the produc¬ 
tion of rubber in very large commercial quantities. 
WHAT THE TREE REQUIRES.—It has always 
been assumed that rubber trees needed a continuously 
humid climate, but it is found the milk is richer in 
rubber and more abundant during seasons of moder¬ 
ate drought. The seeds are quite perishable, and will 
onl(y grow naturally in moist shade, but young trees 
established in the open in comparatively dry locations 
promise much better yields than those grown in the 
shade or in very moist situations. It therefore be¬ 
comes necessary to plant and care for rubber trees 
much as we do young orchards, until they are ready 
to tap at about eight years old. The trees are best 
planted about 10 feet apart, so that they will grow 
with upright trunks. The regions naturally adapted 
to rubber production are much more limited than has 
been claimed and would-be investors would do well 
to look up all reliable data before committing them¬ 
selves. Investigation concerning the real factors con¬ 
trolling rubber production has scarcely begun. It 
seems to be demonstrated that rubber trees can be 
grown where their special needs are supplied with the 
promise of profitable yields, but the same expert care 
and knowledge is needed as in staple horticultural 
operations. The chances are that heavily capitalized 
companies undertaking to plant rubber trees in un¬ 
tried localities will meet with more failures than suc¬ 
cesses. Fig. 309, kindly loaned by the Department of 
Agriculture,' shows the native method of tapping the 
Central American rubber trees. The latex or rubber¬ 
bearing milk is not a tnie sap carrying nutrition 
throughout the tree but is a special se¬ 
cretion contained in fine vertical tubes 
in the bark. Boring and suction devices 
cause only a limited flow, so it is neces¬ 
sary to lay the bark open in long slant¬ 
ing incisions as shown in the cut. This 
is accomplished with a machete, an im¬ 
plement formed like a long heavy corn 
knife, indispensable to the worker in 
tropical forests. The Brazilian tree is 
tapped in about the same manner, while 
the Ficus or African rubber plant is 
often cut in sections. 
IN THE AMAZON VALLEY.—In 187S 
the writer spent several months in the 
Valley of the Amazon, and was detained 
some weeks by the failure of a steam¬ 
boat connection in a little rubber-gath¬ 
ering settlement on a tributary river 
nearly 1,400 miles from the sea. To 
while away the time frequent excursions 
were made in company with the native 
rubber collectors, who lived in the most 
primitive way imaginable. With the 
exception of the ever-ready machete all 
appliances used for gathering and curing 
rubber were either direct gifts from na¬ 
ture or of the simplest possible construc¬ 
tion. Amazon rubber hunters, as a rule, 
are outfitted in advance by the various 
rubber exporting companies. They are 
charged outrageous prices for the cheap¬ 
est supplies and are kept in never-end¬ 
ing debt by a system of peonage and 
constant extortion. As a rule, they 
are cheerful and industrious in their 
calling, and being well versed in local 
woodcraft, are capital forest companions. 
Every hunter at the beginning of the 
dry season searches out a sufficient num¬ 
ber of trees which, on affixing his mark, 
become his property for the season. As 
the forest is a trackless tangle he cuts 
a path from tree to tree, laying out his 
route in circuitous form to the best ad¬ 
vantage. 
LONELY TRAMPS.—In the Amazon 
Valley, lying almost on the line of the 
Equator, the days and nights are of 
equal length throughout the year. The 
sun rises and sets at six o’clock each 
day with startling suddenness to anyone 
not accustomed to equatorial conditions. 
At the first indication of light we would 
plunge into the dark forest, picking the 
way along the slippery tunnel-like path', 
carrying machetes, guns and a net containing several 
calabashes or gourds of about a gallon capacity, some 
empty snail shells as large as a teacup, a ball of sticky 
clay, and an exceedingly simple lunch of turtle meat 
and cassava or mandioca meal. On reaching a rubber 
tree, which has a smooth brown trunk, and generally 
towers up through the leafage until lost to sight, a 
fresh V-shaped cut would be quickly made in the 
bark, or the edges of an old cut not yet exhausted 
would be freshened and a snail shell stuck below the 
angle with a dab of clay. The "milk” looks just like 
MILKING THE RUBBER TREE. Fig. 309. 
