6o 
Sharpies and Lamb our ne. — Observations in 
apparently in the majority of cases always secondary, but are concerned 
with destroying the weakened tissues \ 
Again, the writers are convinced that too much importance is attached 
to results of inoculation on seedlings in the laboratory. No disease on 
mature trees can be considered finally proved until the typical symptoms 
have been reproduced by artificial inoculatiqns on mature trees. Valuable 
information as to the possible cause of the disease on mature trees may be 
obtained by experimental inoculations on seedlings, but more often than 
not this is put forward and is often accepted as proof conclusive. That 
such is not always the case the following series of experimental inoculations 
will show very clearly. 
As we were not attempting to prove a specific cause of Bud-rot no 
attempt was made to identify the cultures worked with specifically. It 
will be convenient for our purpose to tabulate results under group letters, 
the following key giving the necessary information to the organism used for 
inoculating the trees : 
Organism A — Phytophthora faberi (Maubl.j. 
„ B — Red-pigmented bacillus. 
„ C — Sarcimonyces sp. 
,, D — Mixture of B and C. 
The inoculations were made by clearing away the leaves and leaf 
bases on one side of the tree. A suitable point for inserting a small gouge 
was chosen and cleaned externally with spirit ; the instrument was flamed 
before boring into the heart. When the tender central tissues are reached 
there is usually some exudation of water ; if the gouge is now withdrawn 
carefully the tissue from the bore-hole will come out lying in the concave side 
of the gouge. This tissue was inoculated with the various organisms and 
pushed back into the bore-hole with the handle of a flamed needle-holder. 
The tabulated results show that in the Group A inoculations only one 
tree, No. 4, remained healthy up to 8.3.21. Tree No. 7, badly attacked on 
8.10.20 and 9. 1 1.20, is fully recovered on 8.3.21. Trees Nos. 8, 9, and 10, 
attacked at various stages, show no definite signs on 8.3.21, but on this date 
eight trees still show signs of attack in various stages. 
Of the six control trees for Group A , two were attacked by beetles, 
which somewhat upsets the value of the control. However, three trees 
appeared to have a bad attack on 8.10.20, but on 8.3.21 only one tree out 
of five (one was cut out for examination) showed signs of attack. 
The trees in Group B on 8.10.20 showed a rapid and very definite 
attack, seven trees out of eight being very severely attacked. At this date, 
if the red-pigmented bacillus had been the only organism worked with, we 
might have concluded that this was the probable cause of the disease in 
Malaya. All the central shoots were black and decayed, most of them 
