455 
It is clear from these experiments that stirring the seeds round 
in the liquid, whether water or copper sulphate solution, is extremely 
injurious. 
The best disinfectant results as far as germination is concerned 
appear to be from the use of bichloride of mercury in weak solution, 
and washing afterwards without stirring the seeds round. 
This solution might, however, not be strong enough to thoroughly 
disinfect the seeds, assuming they were covered by spores. 
Personally I think the risk of importing seeds with spores of rub- 
ber-killing fungi is infinitesimal. Supposing, for instance, one rubbed 
a seed with spores of Fomes and planted it in the nursery. The 
spores would not last indefinitely and it would be probably two years 
before the plants in the nursery would be old enough to be attacked. 
It is in the highest degree improbable that any of the spores would 
germinate at all under the circumstances. In the case of Diplodia 
the risk would be still smaller, as Diplodia requires to be put on the 
cut end of a shoot to make a successful growth. As I have pointed 
out till decomposition of the exterior of the shell of the seed sets in 
the spores could hardly rest on the smooth surface, and would even, if 
attached by mud etc., or included in the packing, be washed away by 
ordinary plunging in water and probably by the first rain also. 
The case is quite different with stumps or plantlets infected being 
brought into the estate. Here the fungus is established in a thriving 
state on the young plant, and can go on developing there. It is put 
in contact with healthy plants in the same conditions of life perhaps 
even thumb-nail pruned or with buds wounded in some away. By 
planting infected spore producing plants in such a healthy lot, a 
planter would be putting the fungus in the best possible position for 
its development. 
The fungi belonging to the group Polyporei are extremely abundant 
all over the tropics and it is very unlikely that Fomes semitostus is 
the only one that can adapt itself to attack Para rubber. Indeed we 
know that Irpex flavus which used to give trouble with coffee can 
attack Para rubber. Tubenf records thirty species of Polyporei as 
fatally attacking trees in Europe and North America in the same way 
as Fomes has taken to attacking Hevea, and as far as one can see any 
at least of the larger Polyporei in the Tropics could adapt themselves to 
attack Hevea. In Christmas Island I and others collected eleven 
species of Polyporei, and there are probably a great many more to be 
found in wetter seasons. How did these get to this isolated island ? 
Some at least by spores blown for 250 miles from the nearest land, but 
a number of the wood-destroying fungi were undoubtedly brought in 
planks, poles, firewood, old t boxes, etc. It is absolutely impossible to 
prevent this. A bit of firewood on arrival at the port is found to be 
rotten, i. e., it contains mycelium. It is naturally thrown away, 
the mycelium continues to grow, and produces its sporophores. 
Other rotting timber is lying round its spores attack that and 
