SUMMARY. 
L. The first paragraph gives the contents of the preliminary reports of 
1912 and 1913; the first one, treating of the form of canker known as 
”canker-patches” can be summarised as follows. 
Hevea-canker has been found in Java, Sumatra and Borneo. 
The symptoms of canker appear in the following order: 
12 
2 
3% 
40, 
The disease is usually discovered by the cessation of the latex flow. 
In the outer bark claret-coloured patches are to be seen, when 
the cork—layers of the bark are shaved off. In many cases these 
patches begin at the cuts and run downwards. 
A discoloration sets in of the inner layers of the cortex which become 
greyish or slightly brown-coloured just outside the cambium. This 
discolouration starts from the claret-colouret patches, but extends 
over a larger area and subsists after the disappearance of the patches. 
Woody tissue is formed round the dead brown cells in the inner 
cortex, by the action of a secondary of wound cambium. This 
formation of wood in the cortex goes on for several months, per- 
haps for years after the canker-infection is over. 
The measures advisable to get rid of the canker are the following. 
19% 
2e 
Se 
By all possible means lessen the humidity of the plantation and 
give free access to air and sunlight; for this purpose removing the 
intercrops, thinning-out and pruning the trees or draining may be 
advisable according to circumstances. 
Cut out thoroughly all diseased tissues of the cortex but leave the 
cambium undisturbed. Train a special gang of labourers for this work. 
Desinfect the tap-knives by means of formaline and spray the 
stems with Bordeaux mixture. (Desinfection and spraying in thís 
way are not used now any more in Java). 
The second report (1913), treats of ”’stripe-canker”’, a form of canker 
unknown before. 2) 
This form of canker shows a decay of the renewing bark and is only 
to be found in the rainy season in very wet weather. The decay is first 
2) Since known as „black thread disease” in English literature on the subject, 
