1. Nodules are produced in the cortex of Hevea brasiliensis
as the result of an alteration in the latex vessel content.
2. This alteration has not been connected with the attack
of any parasitic organism, b ut appears rather to be due to
physiological changes in the latex.
3. The tendency to suffer alteration in the latex vessel
content appears to be confined to certain individual trees
which have a predisposition to develop this condition.
4. Four types of nodule have been distinguished :—
(a) Nodules formed round altered latex vessels.
(b) Nodules formed round lesions in the cortex into which
latex has oozed and coagulated. May occur in
any Hevea tree.
(c) Nodules formed round areas into which latex has
oozed and coagulated ; the coagulated latex occupies the intercellular spaces without lesion of tissue.
May occur in any Hevea tree.
('d) Nodules formed under unknown conditions round
areas of cortex from which latex m ay be entirely