December i, 1881.] THE TROPICAL 
AGRICULTURIST. 
545 
.COFFEE LEAF FUNGUS: 
MR. MARSHALL WARD'S REPORT AND MR. 
SOHROTTKY'S EXPERIMENTS WITH 
CARBOLIC ACID. 
The following correspondence has been sent to ub for 
publication : — 
From Kuc4iiNE C. Schrottky, to the Hon. the Colo- 
nial Secretary, Colombo. 
Sir, — lu paragraph 20 of the Cryptogamist's third 
report on Coffee Leal' Disease, lately published as a 
Sessiou'd Paper, reference is made to experiments with 
oarbolie acid. 
1. As the short account there deals chiefly with 
experiments that have been carried on for the last 
year under my direction and by my advice, and as it 
is in a great measure incorrect not only in its detailed 
statements but also in its general conclusions, I have 
been asked to furnish you with an authoritative 
account of these experiments, so that it may be 
placed on record supplementary to paragraph 20 of the 
said Report. I have now the honour to do so, in 
justice to myself and in the interests of your go- 
vernment and the colony. My professional work 
as an agricultural chemist having before this come to 
the notice of your government with some apprecia- 
tion (vide Colonial Secretary's letter to me of the 
4th November 1876), I trust I shall be considered 
justified in thus officially addressing you. 
2. In 1 he resumed of my work, addressed to the 
planters' Association, I brought my experiments under 
two distinctive heads, the 1st being attempts to 
render the condition of tho sap of the coffee tree, to 
some greater or less extent, unsuitable for the sup- 
port and development of the fungus, the 2nd being 
expeimi nts with topically destructive applications 
of suitable chemicals. 
3. In his remarks on the 1st set of experiments, 
the Cryptogamist has persisted in giving the same 
peculiar exposition of the principles on which I 
worked and of tho object I had in view, as he had 
done previously in public print, and which on that 
occasion was corrected both by the press and by 
professional men, who styled this said exposition as 
unfair. 
When I commenced these experiments, I con- 
tended that as there were on nearly every estate a 
certain number of individual trees which, year after 
I year, are known, practically speaking, not to suffer 
' from leaf disease, while tho surrounding ones are 
hoa-ily affected (all external conditions being appar- 
ently similar), and as on the other hand there are 
other individual trees on which the disease exists in 
1 a chronic state, which are scarcely ever free from 
' it, though all the rest of the estate may be 
I unaffected by it, these facts, I argued, furnish indirect 
evidcuce that there are certain unknown conditions of 
tin: ooffee tree which are either particularly favour- 
able or unfavourable to the development of the dis- 
ease. 
4. Tho Cryptogamist has given us no explanation of 
tluse i»t ih'i-lnd. facts wi ll known to every planter 
(he conveniently ignores their existence), and the 
above arguments must, tborefore, bo accepted as sound 
and compatible with our present knowledge of the 
life history of the fungu*. His statement that 
j ho ha< failed to obtain any evidence of a special 
predisposition of the tree to the disease cannot, of 
course, lie taken to do away with the fact thai such 
predisposition exists on the part of individual trees. 
G. Such direct evidence as tho Cryptogamist seems 
to require t > confirm facts of practical observation 
will, m ray opinion, never lie forthcoming with our 
present chemical and microscopical means of research, 
no more so than auy direct evidence could bo pro- 
187 
duced why vaccination diminishes the natural liabi- 
lity to infection from smallpox. 
The cause is too subtle — the fact remains. 
6. Holding these views I proceeded to ascertain 
how far the presence or prevalence of certain chemic- 
als in the i-ap of the coffee tree could produce 
conditions either favourable or unfavourable to the 
establishment of the fungus in the stoma of the 
leaf or to its development. To avoid any error in 
mistaking the cause of any observed effect, I did not 
choose to let these chemicals be absorbed by the roots 
but caused their direct absorption into the sap of 
the tree laterally, through the cambium cells of the 
stem. This novel idea, in correctness of principle 
fully accepted by local experts in vegetable chemis- 
try, was, I regret to say, greatly made use of by the 
Cryptogamist to throw doubt upon the bona Jides of 
my experiments. My proceedings were said to be 
opposed to all kuown laws of vegetable physiology, 
presumably because " No one has succeeded in proving 
that either stem or leaf can absorb water through 
their corky or cuticular coverings to an appreciable 
extent"; (so the Cryptogamist states in his letter to 
Mr. Talbot, 28th Jauuaiy 1881). 
It became a question as to who was more com- 
petent to authoritatively decide this point. It was 
delinitely settled by my experiments at " Holbrook" 
proving that such absorption in the case of the stem 
can take place to an extent that I myself would have 
thought almost impossible. 
7. Details of the inoculation experiments, their re- 
subs and the general conclusions they led to, you 
will find in enclosure. 
As the planting public have been fully informed 
by me that eveu the most promising of these ex- 
periments, on account of the evanescent character of 
thw effects and the danger to the tree, held out no 
hope to me that I might find practical means to mitig- 
ate the ravages of the disease by influencing the 
condition of the tree, it. is difficult to understand 
why the Cryptogamist thought it necessary to refer 
to it in his report. 
8. You will observe from enclosure that on seven 
different estates careful observation had established 
that the main effect of inoculation with carbolic 
acid consisted in rendering the majority of pin-spots 
barren. As every pin-spot appears capable under 
favourable circumstances of producing 150,000 spores, 
I think I was justified in considering the effect of 
the treatment in the light of a beneficial result and 
as an important step in the right direction. 
The Cryptogamist's statement that " examination on 
the spot convinced him that no temporary benefits 
were secured," entirely unsupported as it 1% is almost 
puerile in face of the large testimony of both pract- 
ical and scientific observers to the contrary. 
It was of couise quite within the Cryptogamist's 
province to show that wo were wrong in our deductions 
as regards these experiments, but in order to make a 
statemeut. like the above justifiable, he ought to have 
supported it by overwhelming proof, showing : — 
1st. Why the non-fruiting of the majority of pin- 
spots on tho treated areas, considering th it in ad- 
joining untreated areas this fruiting had freely taken 
place during the same perio I of observation, could 
not be considered "a temporary benefit." Or 
2nd. To what other causo or causes this uon-fruiting 
of the fungus on treated areas could bo attributed. 
9. It is with some reluctance that I go into these 
longthy details regarding experiments that havo led 
to no practical results iu my bunds, but my object 
in thus showing that nothing worthy of the name 
of proof has been advanced by the OryptOgamiat 
against tho principles and arguments winch guided 
mo in these mid experiments is— to leave the w aj OJ eu 
for some moro successful experiments iu this direction. 
