55° 
THE TROPICAL AGRICULTURIST. [December i, 1881. 
application of these substances should be so great as to 
be practically prohibitory, not only as regards frequently 
repeated treatment, but even with respect to one applica- 
tion in a year. The cost of experiments ably con- 
ducted by the late Mr. Anton on Harrow estate ranged 
from R20 to R47 per acre, an average of R33-50, or 
say £3. One thorough application of lime and sulphur, 
costing £3, destroys, according to Mr. Schrottky, only 
40 per cent of the fungus existing on the trees. To be 
fully effectual the application should be repeated twice 
again at short intervals, so that the cost would be raised 
to £9 an acre. Now what Mr. Schrottky professes to 
prove, in the correspondence which appears in today's 
issue, is, that carbolic acid, in the form in which he 
applies it, while not open to the objections stated by Mr. 
Ward, either as regards destruction of tissue or injury 
to soil, is effectual in destroying, by one thoimigh applica- 
tion, 70 per cent of the fungus at a cost of only R5 
to R7 per acre, say an average of R6, or less than one- 
sixth the cost of lime and sulphur. Three applications 
of carbolic acid powder would cost only R18, and Mr. 
Schrottky, as we understand him, insists on three applica- 
tions at intervals of ten days to ensure perfect success, 
the area operated on not being less than 100 acres. We 
have gone over the whole question in conversation with 
Mr. Schrottky, and he seems confident of his position. 
Injection of the acid into the cambium of the plant, 
he admits to have been in his hands a failure, while he 
does not abandon the principle involved. But for applica- 
tions of his powder, repeated as indicated, he claims 
perfect success. And we understand him to claim for 
his application an effect winch Mr. Ward has denounced 
as impossible. The Government Cryptogamist insists 
that nothing (short of the destruction of the leaf, of 
course) can destroy the fungus once it is lodged in the 
intercellular tissue. Mr. Schrottky contends that his 
remedy prevents fructification in such cases : the im- 
portance of which fact may be estimated from this 
other, that out of one stoma may come 150,000 spores. 
As we understand Mr. Schrottky, the effect of his remedy 
on the affected leaf is that not one of the possible 
150,000 spores lives to emerge. All this he says his 
experiments have proved, and, if he is correct in his facts 
and deductions, we need not dwell on the importance of 
the issue. In the course of a long conversation, in which 
bur enquiries were very searching, Mr. Schrottky revealed 
to us the composition of his powder. He did not enjoin 
secrecy, but we do not feel at liberty without his per- 
mission to publish the constituents of the powder, almost 
impalpably fine, which he employs. It is prepared ex- 
pressly for him by Calvert's firm, and we may say that 
the absorbing substance is not clay, while the proportion 
of acid is far less than that contained in the common 
preparation winch Messrs. Lewis Brown & Co., Calvert's 
agents, advertise as " 15 per cent powder." This means 
that 15 per cent of carbolic acid, which is in the nature 
of an alcohol, is in this case mixed with clay. When the 
acid goes off in the form of gas, which it gradually will 
- < :posed, the inert clay will remain, and, obviously, 
its effect on coffee soil would be almost nil. In the case 
of Mr. Schrottky's powder, the acid is not only far less 
in proportion to the solid matter than 15 per cent (so 
that while fatal to the fungus it does not destroy leaf 
tissues) but the residuum, instead of being merely inert 
like clay, or injurious to the soil, as Mr. Ward mis- 
takenly imagined, is positively beneficial to the soil as 
a fertilizer. 
Steeling clear of the controversy between the scientists 
— one eminent as a mycologist while the other has the 
no small advantage of being an experienced chemist — 
we have thus endeavotu-ed fairly to represent the main 
results of experiments conducted by Messrs. Marshall 
Ward and Schrottky. Gratitude is due to each for 
valuable additions to our stock of knowledge in regard 
to a painfully interesting question. Mr. Schrottky, how- 
ever, claims for his carbolic acid powder superior qualities 
of cheapness and effectiveness, which, we submit, demand 
attention not only from planters, who are so deeply 
interested, but from the Government to which Mr. 
Schrottky^ paper is directly addressed. Before Mr. 
Marshall Ward leaves the island, we trust that he, in 
conjunction with Drs. Tiimen and Thwaites, and per- 
haps some other naturalists or men of science, may be 
requested to aid a committee appointed by the Planters' 
Association, in thoroughly testing by a complete set 
of experiments the correctness or otherwise of the effects 
which Mr. Schrottky claims for carbolic acid powder as 
prepared for him. The preparation being very different 
to that which Mr. Marshall Ward, under a natural enough 
misapprehension, condemned, there can be nothing incon- 
sistent in his taking part in the proposed enquiry. 
But, if all that Mr. Storck of Fiji alleges can be 
substantiated, then a perfect cure for Hemileia rastatrix 
has been already discovered in that island of the south 
to which we sent the cofiee fungus with the coffee seed. 
We in Ceylon are not too proud to receive good in 
return for evil, and we shall look with very deep interest 
for the advent of Mr. Storck, who thus writes to thej 
Fiji Times : — 
Sib, — In contiuation of former publications on the subject 
of coffee leaf-disease, I wish to communicate another 
short paper with a view of dispelling certain incorrect 
impressions held by the general public, and which are 
even shared by experienced planters, who might have 
been expected to know better. The most widely dis- 
seminated and at the same time most discouraging belief 
with coffee planters, consists in the erroneous notions on 
the term of life enjoyed by the units of the fungus, 
which is in reality very short. Leaving on one side all 
microscopical and physiological speculations, we may con- 
sider the red rust appearing on the under side of a 
diseased coffee leaf as a mass of seeds, which practically 
speaking, partake more or less of the nature of any 
other seedling. 
It is a fact sufficiently well established by scientific men, 
and other close observers of nature, that Hemileia Vastat- 
rix lives and preys upon no others but the coffee plant, 
just as Botrytis Infestans confines itself to the potato, 
and Oidium Tuckerii to the grape vine. Of the number- 
less spores of the coffee fungus, thousands of millions alight 
upon uncongenial bodies, whether organic or inorganic, 
there germinate and perish for want of congenial food 
and shelter. Comparatively few only reach the under side 
of a coffee leaf, and finally succeed in finding their way 
through by means of their germs into the cuticle of the' 
leaf and there establishing a new root-stalk or mycelium. 
Were the natural propagation of the fungus not so pre- 
carious, no coffee plant could live where it is once habilit- 
ated. The spores are said by scientists to germinate 
within from one (?) to seventeen days, and this space 
practically determines the extreme age of a spore under 
natural conditions. A great deal has been made of the 
circumstance of spores of the fungus having been kept 
and their vitality preserved in letters, that means be- 
tween dry paper, for two years, and which is quie 
likely. The spores of ferns, especially similar to those of 
