138 
THE TROPICAL AGRICULTURIST. 
[August i, 1896, 
Mr. Lawson’s own Dodabetta. That there may be 
mineral ingredients sufficient in these soils is not 
denied, but analysis of the Wynaad soils shows no 
lack of these mineral ingredients either. 
One of our overseers, who has been at planting 
for many years, takes the very opposite view to Mr. 
Lawson and says “ canker is due to richness and 
not proverty of soil.” 1 am not inclined to go all 
the way with him in this statement, but I think 
he is nearer the truth than Mr. Lawson. 
Why else is there so little canker in cinchona 
planted in sterile grassland, such as that of Liddles- 
dale, Belleview and other estates at Neduwattam, 
and Ooty 2 Very much to the point is a clearing 
near here, at Devicolum, where a patch of grass- 
land cinchona adjoins, and is under the same 
conditions in every way, as a plantation in felled 
forest land. The latter has suffered from canker 
here and there, the former not at all. And here I 
would call Mr. Lawson’s attention to a fact he is 
either ignorant of, or has ignored. I mean the fact, 
that there are certain jungle trees, the dead roots of 
which will kill out tea, coffee, and especially cin- 
chona. Perhaps this is the explanation of patches 
among otherwise healthy cinchona, planted in forest 
land, and their non-appearance in grassland. 
I would also add that for the actual growth of 
the cinchonas, and for the analyses of their barks, 
a rich soil, either naturally so, or produced arti- 
ficially, is no doubt preferable, but these questions 
are wholly apart from that of canker- 
After all this denial of Mr. Lawson’s theory on 
canker, you will expect me to pronounce a theory 
of my own, yet I must own, that I hardly have 
one, and every planter worthy of the name will 
approve me, when I say that all theories on the 
subject are and can at present be mere guesswork, 
or at the best an honest attempt at deducing from 
visible facts. Such, however, as my opinions, on the 
subject are I will give them, and your readers must 
take them for what they may be worth. It is then 
my belief that there are three diseases that attack 
cinchona and can prove deadly to it, call them canker, 
or anything else you like : — 
Istly, a disease which begins at the top of the 
tree, sometimes at the end of the branches in the 
shape of a withering and drying up of the leaves and 
younger wood. I would ascribe this to not enough 
sun; in some clearings to a windy aspect. This 
rarely, hardly ever proves fatal. 
Secondly, there is the disease which attacks the 
roots of the tree, sometimes working from the feeders 
upwards, sometimes from the collar downwards. 
This is always fatal in the former case. In the 
latter, if the evil be perceived before the whole of 
the collar is affected, a cutting away of the affected 
part which outside has a red or black, inside a 
rotten white appearance, may save the tree, at all 
events for a time. This disease I attribute to a 
clayey subsoil, a lack of drainage in the sub or 
surface soil or, to the effect that wind has had on 
the plants when young, bending them to and fro, 
and thus hardening “ultra fas’’ the tissue at the 
point of resistance, i. e. the collar. 
Thirdly, there is the disease, which attacks any 
part of the stem from the collar to the second 
or even third set of primaries. This is a sort of 
desiccation of the bark in parts, followed by a 
congestion in others. We planters, in perhaps 
unscientific, but very expressive language, say this 
is due to the plant being hidebound. Taken at 
an early stage, and other circumstances being 
favourable, it can sometimes be remedied by running 
a knile up the stem, thus liberating the flow of 
sap. But circumstanoes as a rule are not favour- 
able, when this species of disease sets in, and I 
would, from my experience, attribute by fur the 
greater proportion of the mortality among cinchona 
in India, at all events, to the latter form of canker. 
That it is due to a stoppage of the flow of sap, is 
proved by the fact, that exudation sometimes sets in 
below, or beside the part afiected, and that princi- 
pally at the times of year, when sap rises abundantly. 
I would attribute this disease to drought princi- 
pally, such drought as is general in India during 
January, February and March. It stands to reason 
that it is far worse at low elevations where the 
heat is greater, and high and intensely dry winds 
usually prevail during these months. 
At such lower elevations the desiccation of the 
bark is more or less universal (though less felt in 
sheltered parts) the cambium is so “hidebound” 
by the shrunk bark, that it cannot pass the rising 
sap : hence the latter exudes or is dried up in the 
bark. “Pas de sang pas de vie,” and the tree dies. 
At higher elevations this form of canker is rare ; 
when it does appear, as a rule it only desiccates 
the outer bark, and is therefore often remedied 
by above process of running a knife up the stem. 
Even at lower elevations, I have kept a clearing 
of cinchona alive for a year or two, when suffer- 
ing from this disease, by ripping up the bark on 
both sides of every tree. Not that I expected 
those trees to live indefinitely, that I knew was 
hopeless, but because I hoped to and did get a crop of 
renewed bark. Such then is my theory, faulty 
no doubt, but the result of past and present ob- 
servation and experience of my own, and my 
brother planters in this district, which must, in 
its lower elevations, resemble other districts, among 
them the Wynaad. 
As for the cinchona planters of the latter district, 
I have no message of hope for them. I would not, 
as I may have seemed to argue, advise their plant- 
ing up their grasslands with cinchona, but on the 
other hand, I cannot advise their planting up their 
forest land or trying to keep up their present 
clearings, at all events those parts affected by canker. 
Mr. Lawson argues from the fact, that there are 
still enormous cinchona trees in the Wynaad, and 
tries to deduce therefrom that thousands of other 
giants may yet be reared. But Mr. Lawson’s pre- 
mises must be statistically strengthened before we 
can accept them. Those giant cinchonas are prob- 
ably the result of the survival of the fittest, both 
as to plant and locality. They were probably planted 
with others, and the others died. And so in the 
future, only with larger numbers the others will die, 
and some few remain. Beyond all this, however, 
there is a circumstance, which Mr. Lawson has 
not even touched upon, I mean the possible, nay 
the certain deterioration in the seed, from which 
present plantations have been reared, as opposed 
to that] from which the older plantations have 
grown up. 
Those old giants of the Wynaad and elsewhere 
are no doubt the result of seed, either imported 
direct, or taken from trees not barked. This, un- 
fortunately, has not been the case with seed used 
for most of the later plantations, which has, as a rule, 
been taken from trees previously weakened by 
cropping, and that too of the old stripping kind. 
In proof of this I will only mention, that a few 
years since when there was such a scramble for 
Ledgeriana, seed was sold, stated to be off trees giving 
from 7 to 14 per cent sulphate of quinine, i. e. not 
only must the parent trees have been barked, but 
the analysis must even have been obtained at least 
after the second barking from renewed bark. Let this 
vitiated seed be put among circumstances somewhat 
adverse and disease will immediately fasten on the 
plant nor will the latter have strength to rally. Put it 
among healthy circumstanoes, and, like a puny 
child well cared for, it may pull through. 
