FORMATION OF NODULES. 
267 
Where several small nodules occur close together their cambial 
layers may meet and unite, thus producing a multiple nodule. 
Often a large nodule in its growth meets and fuses with small 
nodules, which then appear as excrescences of the large nodule. 
The older nodular masses vary considerably in size and 
shape. Some specimens are much developed in thickness, 
and project very considerably from the surface of the stem ; 
some of these measure 3 or 4 feet in length, 6 or 7 inches in 
breadth, and 3 or 4 inches in thickness. At other times a 
plate or sheet of nodular tissue is formed. One such plate at 
Peradeniya measures 4 feet 9 inches long, 6 inches broad in 
the middle, and 1 to 2 inches thick. 
Occasionally nodules are obtained which exhibit a network 
shape strongly resembling the network of a latex vessel 
cylinder in tangential section. This type of nodule exactly 
represents what would occur were the latex vessels to be 
encysted by layers of woody tissue, and as will be seen later 
this appears actually to be the case. 
At a very young stage nodules of only a few milhmetres 
diameter may develop a vascular connection toward the wood 
of the stem ; some nodules apparently never develop any 
vascular connection. This vascular connection ultimately 
reaches the wood of the main stem, the cambial layers unite, 
and the wood of the nodule thus becomes united with the stem 
wood. As the nodule grows more vascular connections are 
formed, and thus large nodules become united with the stem 
wood at many points. In the case of thick, massive nodules 
large areas of the nodule may become united with the stem 
wood, but no cases have been observed of complete fusion 
between nodule and stem. In the case of plate and sheet 
nodules fusion occurs to a lesser extent, the vascular connec- 
tions remaining more or less isolated. Hence between such 
large nodules and the stem wood there are considerable areas 
of the original cortex. 
Similar vascular connections are sometimes developed from 
the stem cambium and proceed in an outward direction 
toward the nodule. In addition, the surface of the stem wood 
is pitted, these pits corresiionding in position with the vascular 
connections from the nodule. The surface of the stem wood 
