July t, 1889.] THF TROPICAL AGRICULTURIST, 
13 
with much recognition is owing to a bad habit he has 
of speaking contemptuously of those who are not in 
agreement with him, and of not dogmatising. What 
right have we, who are empirics at the best, with but a 
smattering of agricultural knowledge, who have never 
been working in a laboratory, who have carried out no 
scientifically conducted experiments, who have but the 
vaguest knowledge of vegetable physiology, to decide 
authoritatively on a question outside our ken ? 
Let us now consider this question fairly and dispas- 
sionately. To begin with, what is smoke? It is the 
moisture contained in a substance that is burnt passing 
off in the form of vapour. We all have observed that 
the more m dsture there is in a substance burnt, the 
denser the smoke, and vice versa. When a substance is 
subjected to the action of fire, which is a quicker 
method of decomposing it than by natural means, the 
organic portion of it is dissipated. Therefore, there 
will pass off with the smoke a quantity of carbonic acid 
and ammonia. Agricultural chemistry teaches us that 
all plants are composed of organic substances, supplied 
to them from the atmosphere, and inorganic or mineral 
substances drawn from the soil. We are further tauuht 
that leaves absorb not only carbonic acid, as " Old 
Planter'' asserts, but also small quantities of ammonia, 
an d both these substances form the organic portion 
of all plants. Carbon, which is derived from carbonic 
acid, plays a very important part in the structure or 
composition of the plant. The question now resolves 
itself into whether the absorption of carbonic acid by 
the leaves is dependent on the supply ; or in other 
words, whether they take up all or mostly all supplied 
to them by fires burned underneath them. This is a 
subject on whicb nou-professionals cannot express an 
ex cathedra opinion. In a conversation with the uew Head 
of the Agricultural School, I discussed this question 
wit h him. I asked him if it was possible by increas- 
ing the supply of carbonic acid by fires under our 
coconut trees to increase the demand for it, aud whether 
it was possible that the stom tta of the leaves became 
(jjstended and more receptive by the action of the fire 
dnd therefore took in larger quantities of carbonic 
acid than under natural circumstances. He said he 
did not think so. I also told him that the late Mr. 
Carry of Kimbulpitiya asserted in a communication 
to the press that he increased the number and size 
of his nuts more by smoking his trees, than by the 
aplication of the best manures ; and that my contention 
was that if such good results did follow smoking — 
"vaporization " as he termed it — they were due more 
to the mechanical and chemical changes in the soil 
by the action of fires and to the residual ashes 
than to smoke. He agreed with me. 
To t est the efficiency of smoke, it will be necessary to 
choose a field of Coconuts without a habitation on it, 
and to burn fires in furnaces well away from the ground, 
■Bnd not apply the ashes to the soil. I think an experi- 
ment couducted on these lines will cure the most enthu- 
siastic believer in smoke by its inefficiency. 
Now that I have indicated the opinion of the present 
Head of the Agricultural School on this subject, I hope 
" Old Planter " will not clamour for the School being 
closed. — B. — " Examiner." 
«. 
THE COCONUT LEAP DISEASE. 
The Observer has a few remarks on my communi- 
cation on the above subject which I propose to discuss. 
To my thinking there is a vast difference between 
Dr. Trimeu's "innutrition " theory, and my theory of 
" a disease caused by innutrition." His referring me 
to the roots and the soil to find the cause of the disease 
led me to regard the word as synonymous with "star- 
vation," caused either by an insufficiency of roots or 
by a poor soil. I look upon the disease, not so much 
as a vegetable "parangi," as a vegetable "scurvy." 
Medical men are, I believe, unanimous in their opinion 
that this latter disease is caused by the absence in th'> 
dietary of human beings of one essential constituent of 
food. Give human beings food in any quantity abound- 
ing in all the essential constituents of food s ive this 
one, and scurvy will be the result. Was not the scale 
of the dietary of our jails raised to its present attractive 
proportions owing to the report of medical men that 
scurvy resulted from an insufficiency of nitrogenous 
food ? I say, that the natural home of the coconut 
palm is by the sea-shore, and in a soil impreenated 
with salt. By cultivating it in inland districts, it is not 
grown under natural conditions. Salt is a dominant 
constituent of its food, and its cultivation in soils with 
an insufficiency of salt renders it liable +0 disease. Whv, 
it may be asked, did not disease show itself before now, 
considering that coconut cultivation in such soils is not 
an industry of yesterday? We know that certain con- 
ditions are necessary for the development and spread 
of disease. Medical science teaches us that insanitation 
leads to certain diseases. Insanitary surroundings help 
to the outbreak of sickness only when the conditions 
for its development are favourable. To take a more 
apposite example, old Planters have certified that they 
were acquainte 1 with coffee leaf-disease for over a score 
of years before it arrested attention. They thought 
nothing of it, as it did no harm. Dr. Thwaites said 
that the fungus existed for long in the jungles, before 
it found a congenial home on our Coffee trees. What 
were the conditions that favoured its assuming an 
epidemic form aud attaching itself to Coffee ? Opiniont 
are divided on this point. Scientists say that the con- 
ditions were the violation of a law of nature that is 
abhorred large expanses of any one pro luct. The dis- 
ease vindicated that law, but has disease left the Coffee 
plant now that the balance of uature has been righted ? 
Most emphatically no. WherPver a Coffee plant is, 
there will the fell disease be found. Others say that 
the causes of leaf disease were climatic, others agaiu 
atmospheric, and that there is a somethiug in the 
climate of the hills now inimical to the growth of fruit, 
but favourable to the growth of loaves, and is the atmos- 
phere favourable to the growth of the deadly fungus. 
As everything mundane is governed by cycles, the old 
climatic and atmospheric conditions will re-appear. 
This belief has the merit of being consoling, but what 
are the grounds for it ? Eternal Hope. 
May a merciful Providence guard coconut trees from 
such a visitation ! Where, in the European, failure 
only helped to bring out in bold relief his innate qualities 
of determination and pluck, the Oriental may be over- 
whelmed and paralysed with despair. This cooonu 
leaf disease is no new thing. Every coconut tree, mor 
or less, has its leaves discoloured by spots. I had plant 
with their fronds looking as if fire had passed ove 
them for many years back, and they attracted onl 
passing atteutiou. This year I saw an aggravation o 
these spots and a large number of trees affected, bu 
even then it caused me no alarm, till meeting- a gentle 
man in Colombo at the end of January, whose dutie 
took him into the country in a radius of about 20 mile 
of the capital, he asked me if I had noticed a peculia 
affection of the coconut leaves. He met it everywhere 
in his journeys in the country. I theu knew for the first 
time that the affection was not local, and on a further 
aud careful examination of my trees I was impressed 
with the severity of the attacks of the disease. As I 
noticed fungus in the withered spots, I thought the 
affection fungoid : Dr. Trimsu thought fungus only an 
effect. The subject absorbed a good deal of my atten- 
tion, an 1 I came to the conclusion that the disease was 
probably due to a want of salt in our soils, and was 
possibly developed by the abnormal weather of last year. 
Mr. Jardine, a very experienced aud intelligent Planter, 
after a visit here was of opinioo that our stiff soil was 
the cause of the affection ; that during dry Seasons 
the roots were earth-bound and inert and supplied no 
nutrition to the tree. This caused the sap to be dis- 
eased, and probably sweetened, and invited an attack 
of bug. The remedy he suggested was a thorough working 
of our soil. He apprehended a cessation of the attack 
when the rains fell aud favoured the pa sage of the 
roots through the soil. In refutation of his opinion 
that the mechanical condition of the soil was res- 
ponsible for the attack, I pointed out to him trees 
growing in a free soil attacked, and I can even now 
show large trees in bearing, growiug on a perfectly 
free soil, with their leaven punctured. He asked 
me to water a plant and break up the soil round 
it thoroughly and watch results. I did this to four 
