December i, 1881.] 
THE TROPICAL AGRICULTURIST. 
523 
no effect lasting 1. 
that re-infection ta 
a very short space 
through the air or 
ately around. 
The Expt 
on Harrow (and^ali 
other estates) niad( 
thods to coftee whe: 
and this I have b 
ness of Mr. Talbo 
an experiment am 
A field of known 
longitudinal halves, 
rapidly, £reshly-bur 
for the double pur 
it comes in conta 
which will rapidly 
crop will bo picked 
areas, and it will 
far the success in 
the lime used. 
The experiment 
servo as a further 
continuous rain tiu 
a top-dressing of s 
part. I contemplal 
concluded, if result! 
by spores carried bodily 
from the leaves immedi- 
Wa/luhti Kslate 
§ 20. I 
account its 
-on a living 
imposes of 
invited to 
Wrappers v 
enclosing ;i 
between the w rapper and the bark of the tre 
the erroneous supposition that tho cork-clad bark and 
the cambiiun could absorb the liquid with benefit to 
tho diseased tree, the object of tho inventor was de- 
clared to be to "deal with tho disease after it has 
entered the leaves." I pointed out the reasons why 
this could not succeed, and also took occasion to insist 
on tho dangerous properties of carbolic acid in connec- 
tion with living coftee. 
Some months afterwards the ill-effects of the treat- 
ment were still visible on trees at Pallekelle, Roseneath, 
'and Peradeniya estates. The caustic liquid having de- 
stroyed a more or less complete ring of bark, cambiiun, 
Ac, had injured each tree to a corresponding extent. 
Examination on the spot at intervals after the experi- 
ment convinced me also that no temporary benefits 
nee secured. Another series of experiments, based on 
sounder principles, have been made as follows : — An in- 
timate mixture of fine clay powder containing 12 to 15 
per cent of carbolic acid is mixed with lime, also hi 
me powder, and the mixture thrown by coolies' hands 
on to tho diseased leaves in the same manner as with 
sulphur and lime. 
The object of using lime here is, however, different 
from that aimed at where sulphur is used. Carbolic 
acid is very slowly volatile, and with difficulty soluble 
in water, and where drops of the acid touch a leaf, &c, 
Detraction of tho tissues ensues.- Carbolic acid has, 
moreover, a powerful odour, aud it appears to be assumed 
in tho experiments that the odour is a measure of so 
Eraoh vapour passing off from the mixture to he dissolved 
in the water on tho leaf. 1 do nol find, however, that 
fl>o destruction of llemileia spores in the neighbourhood 
of the mixture is commensurate with the alleged results. 
It is true that where water is in contact with the pow- 
der 11 solution is obtained sufficiently strong to kill 
germinal tubes, but the diffusion of this over the leaf 
* I doubt whether tho effect lasted more than week. 
leparately from the two 
ible to determine how 
leriment depended upon 
proceeding on Peradeniya will 
*, since the mishap of rapid and 
the application, practically, into 
ir and lime salts for the most 
ained. 
le tree 
I mud 
Under 
is a very slow process. Under any circumstances the 
results of experiments with carbolic acid powder are not 
as yet encouraging, though I am of opinion that more 
might be done with some modification of it,* if it were 
not for the fact that the accumulated powder and solu- 
tion an: a source of danger at the roots. 
I will pass on to the description of a few illustrative 
experiments before reporting further on the larger ones. 
A sturdy coffee plant, of which two leaves were diseased 
with " rust patches," was placed in a small wardian 
case, the wdiole of the inside of which was painted with 
a saturated solution of carbolic acid hi water. In the 
overpowering atmosphere produced the plant was tightly 
enclosed. After 24 hours I opened the case and removed 
the odour of carbolic acid was so strong, that 
with difficulty hold the head in the enclosure. 
5s, spores taken from one of the patches ger- 
.minally hi 24 hours. It is thus clear that in 
ilic acid (as with other reagents) the germinal 
of the acid, 
subject. A 
powder and 
raid around 
ic watering 
when one 
d the leaves 
i effects of 
the 
tubes will have to be attt 
Another experiment th 
tliin layer of the mixtur» 
lime was sprinkled on th 
two coftee plants, and at 
of the 
of the 
even i 
disasti 
they 11 
But 
and I 
other were pale and drooping, 
dilute solution of carbolic acid at the roots are 
ms, though in the case of a large strong tree 
ly he to a certain extent masked by other changes, 
observations on wdiole estates prove the same, 
have failed to discover the good effects said to 
have been produced on estates by the treatment. That 
the germinal tubes are killed wherever a solution of 
carbolic acid comes hi contact with them is true ; but 
such a solution is not produced in the way described in 
the experiments on Peradeniya, Gleneagles, Pallakelle, &c. 
If carbolic acid powder could be used with safety, it 
would be more efficacious without the lime, which could 
be used with benefit as a manure ; but in face of the 
fact that whatever external application were used, it 
would have to he repeated at least every three weeks or so, 
it would be highly injurious to permit such an increase 
of carbolic acid in the soil as would be the case here. 
Sec. IV. — On the " Origin* of Leaf Disease." 
§ 21. The story of the discovery of the fungus Ilemi- 
leia vastatrix by a well-known planter in Madulsiina in 
186!) need not be repeated in detail here ; hut since a 
general impression exists that the year of its discovery 
lias connection with the date of its introduction into 
Ceylon, that because it was first seen hi Uva, it necess- 
arily originated there, I would call attention to facts 
which throw the gravest doubts on such a view, if they 
do not invalidate it altogether. 
I am told that when llemileia was first seen on the 
coftee it was already common on the estate, and, in- 
deed, on a neighbouring estate as well, and it is doubt- 
ful whether it had not already been observed in other 
parts of Ceylon. An examination of the weather reports 
in 1869 on the estate where the discovery took place 
show s the following : — 
March, 186!), was very dry, and April tho same up 
to the 12th, when the wet set in for a fortnight or so. 
During May were showers at intervals, but cloudy, hot 
weather prevailed. Now, it was about .Tune 1st, 1869, 
that Hemileia was first observed, and the spores which 
produced the spots then noticed no doubt germinated in 
April ; for in the first place, the spots icere advanced 
and numerous, and in tho second, the haves icere already 
falling. In September, 1870, the diseaso was found in 
Nihunbe and Hantane, and was there also in sonio 
• As, for instance, using the weak powder alone on 
the leaves, and tho caustie limo separately as a top- 
dressing to the soil. 
