222 
As Dastur states, this description clearly shows that Line- 
Hage in Java is identical with Black Thread disease of Hevea 
n Burma, but he points out that it % not clear why Rutgers 
obnaiday the two forms, i.e., Form A and Form B (the latter 
including C and D described above) to be due to the same fungus, 
Phytophthora Faberi. For although he inoculated Hevea with 
Phytophthora obtained from Cacao and obtained the typical 
canker Form B in every case, vet when he inoculated Hevea with 
Phytophthora from Hevea he obtained the typical black vertical 
stripes of Form A. It is unfortunate that the Phytophthora 
found on Hevea has not been inoculated on Cacao either by Petch 
or Rutgers. 
Diseases on Renewing Bagk in Malaya. 
Rutgers paid a short visit to Malaya during 1912 and reported, 
as a result of an inspection of burred trees, that Form D 
described above was present on Malayan plantations, This 
feature never assumed serious proportions and perhaps is now 
less noticeable than at the time of Rutgers’s visit. Little atten- 
tion was given to this manifestation. In 1916 two serious affec- 
tions of renewing bark were under observation in widely separ- 
ated districts of Malaya. One district is in North Perak, the 
other in the Negri Sembilan. Both districts are well inland, 
the affected estates being situated on undulating land. 
Bark Canker (Black Stripe) in North Perak. 
The symptoms of the N. Perak outbreak closely resemble those 
described for the Black ‘Thread of Burma and the Line-canker of 
Java, but the blackening of the tissues along the whole cut as 
mentioned both by astur and Rutgers is seldom observed except 
in long 8 ea cases. The vertical black lines remain 
The diseased Pains when cut into with a scat gouge ieee 
not only to the wood but penetrates deeply into it. Other 
observers have not recorded this penetration of the woody tissues; 
they simply state that it extends through the cambium into 
the wood without calling attention to the fact that this observa- 
tion may be of fundamenta importance in a consideration of treat- 
ment. In N. Perak, cases have been noted where there was 20° 
external indication beyond a small slightly discoloured spot, yet 
excision reveals the wood diseased to a depth of } or } of an 
inch with a vertical extension of one inch. The penetration in 
a radial direction must be very rapid, for cases haye been exam- 
ined showing discoloured wood to a depth of an inch which could 
only have originated from fabian: made seven to ten days 
previously if the infection takes place on the tapping cut. The 
fungus can be demonstrated in the discoloured wood at its deepest 
part. This radial penetration wk the wood is so extraordinary 
that special attention was given to the progress of the fungus 10 
the tissues. Dastur (3) “states ‘that the fungus seldom runs 
below the tapping cut in Burma though _Petch and Rutgers 
record instances where the Black Stripe decay travels downwards 
to imvolve the untapped bark. These cases appear to be excep- 
