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great difficulty adapting to the life required in rubber-growing areas
along the Amazon River and its tributaries. The laborers that did survive
were horribly exploited, in an almost slave-like state, and there was little
sharing of the great wealth derived from their efforts.

Interest in the development of plantation-grown rubber in the Western
tropics was stimulated during two world wars, when the regular supply was
cut off. The United States Government subsidized research and carried out
large programs to help Brazilian rubber specialists to overcome the disease
problem. However, at the end of each of the wars, in an economy-mood, and
with pressure from the synthetic manufacturers, all the efforts stopped,
without any great advances toward the solution of the difficulties. The
solution of the disease problem takes long-term support because determina-
tion of disease resistance and high yield require long periods of time. The
research required cannot be performed in the length of time that the wars
have lasted, and to build up competence in the work, research specialists
require time, much more than that allotted. Many approaches to develop
plantations of disease-resistant, high-yielding trees have been tried, but
the most promising one yet developed is the breeding of the disease-
resistant varieties. While the disease can be controlled by spraying with
fungicides, the expense of such an operation is prohibitive in lands where
high rain-fall is a constant condition. The breeding of resistant types is
also a very discouraging, slow procedure, and very expensive.

In general, and without all the details, the methods of developing new
resistance is as follows: first, seeds from native plants are germinated
in seed beds, and when the young plants have sufficiently developed, are
set out in nursery beds. When the plants are about two feet tall, cuttings
of high-yielding varieties developed in the eastern tropics are grafted onto
the seedling root stocks. These grafted plants are again transferred and