654 
THE TROPICAL 
AGRICULTURIST. [January 2, 1882. 
011 the mother plant, but, however far the juices of a 
suffering plant may be vitiated, I do not see how 
sach a condition could take place. Tbe theory reads 
to the plaiu observer of nature something like a 
sensational novel to the lover of standard literature: 
it is overstrained and artificial. Plenty of Ceylon 
coffee seed has boon sown in this country a few 
years past, but none of the offspring ever suffered 
from Hemileia vastratrix until it was bodily imported 
on live coffee plants. 
For more than two years now I have been a close 
observer of Hemileia vastatrix, and have proved that 
whoever superstitions of its wonderful powers of 
dissemination and vitality rnay be abroad it does 
neither infest the soil nor the air in any other manner 
than other seeds, with superior means of traversing 
the air, and thereby widening the zone of their geo- 
graphic d distribution. As regards its vitality upon the 
surface of the soil or other uncongenial bodies, that 
is 1 eterm-ined by the time it takes for germination, 
and finding food for the germ in a coffee- leaf. In 
the absence of that it must as surely die as any 
other seed germinating under conditions adverse to 
vegetation. The circumstance of spores of Hemileia 
vastatrix having lived and germinated after being 
kept for two years in a letter has surrounded it with 
a spectral halo of i mmortality which has made many 
despair of a successful treatment. I have known the 
spores of ferns under parallel conditions, i. e. kept 
jii dry paper between the sheets of herbarium, 
germinate readily after more than 20 years 
from the time of collection. I have seen stumps of 
old coffee-trees, that were left after the destruction 
of a field thoroughly infected with Hemileia vastatrix, 
sprout again and grow apace f,-ee from it, because, 
being old and sluggish of growth, the fungus had 
actually died a natural death, before it could find a 
home in the new growth made by those stumps. 
My first attack upon it was made by direct applica- 
tion, on the principle of exhausting the spores con- 
tained in the tissue of the leaf by killing them as 
they come out. I succeeded in this with all (some 
30) the trees, applying moderately caustic lime only, 
after about eight week* of daily applications. They 
ara the same batch of trees that, were spoken of in the 
Observer, and continued clean for (most of them to 
this day) a twelvemonth, when some of them were 
accidentally reinfected by a gang of Fijian labourers 
from the Upper River. The result proved to my satis- 
faction that a thorough and lasting cure was possible. 
At the' same time, I became aware that this or 
any method of manual (direct) application was too 
laborious, even though weekly applications only would 
perhaps have answered tbe same purpose It is open to 
failure through interruptions by stress of weather 
and the negligence of labourers, and every interrup- 
tion would of necessity mean the whole work over 
again. Whilst working at and watching the effects 
of this experiment, I had been thinking of a method 
of vaporization, which could be made automatic and 
permanent. The principle suggested itself to me 
partly though Mr. Morris' more recent sulphur and 
lime treatment, and through what I had seen prac- 
tised when a younger man at home, but under the 
shelter and confinamet of glass-roofs. But the prob- 
lem to be solved was : how to adapt the system to 
the open field. The outcome of my cogitations and 
experiments is my 
Method of Permanent Vaporization, which I hereby 
recommend to the planters of Ceylon and all othr coftee- 
growing countries suffering from Hemileia vastatrix 
The chief features of the system are: — 
(I) The greatest simplicity. 
$) The greatest economy of material and labour 
13) The most perfect control. 
(4) Complete isolation of material from soil & plants. 
(5) Unparalleled cheapness. 
(6) Ab.-olute and unconditional exemption from 
leaf-disease, 
(7) The larger the area treated the better. 
An average man can attend to fifty acres a week 
or more, and the bulk of the material is to be found 
on every estate, meaning a saving of 90 per cent in 
carriage, as compared with that of the materials 
hitherto used against the fungus. 
The cost of the first year's treatment will not ex- 
ceed £2 per acre, and that of any subsequent year 
be less than £1. The centres of vaporization in the 
field have to be supplied once a week, and the treat- 
ment may be started at any time, whether leaf- 
dis-as- be visibly present in a field or not, with 
equal advantage. In the latter event, 4 weeks of the 
application will brin<; out every pinspot in the field, 
kill them, and save the greater part of the foliage. 
If, on the other hand, the fungus in a field be in 
full vigour, you will notir-e the action of the specific 
in the following manner : — Three or four days af ler start- 
ing the treatment, the spores will show a change in color 
from bright orange to dull ochre, until they turn 
from dirty yellow to greyish white. They all, ii stead 
of dispersing, stick to the leaves until they vanish 
from sight. In the second month, all rust coming 
out begins to look dull in color and sickly ; many 
rust patches begin to show pale rings round them, in- 
dicating the, limits of the mycelium, where its farther 
formation has been arrested. After the second mouth, 
a large proportion of the spots have white rings 
round a yellowish centre, as it drying up in the middle ; 
sometimes they push out a few sickly spores, bat 
oftener none at all. The spots then turn iuto dry 
tissue, and, unless the leaves had been, too thickly 
charged with fungus, they remain on the trees. Thence- 
forth a little dirty rust may still appear, but the 
presence of the fungus will be chiefly indicated by 
dead and dying mycelia until it vanishes altogether. 
By this time a field of fairly vigorous trees will have 
recovered its full coat, or nearly so, of foliage, wl ich 
under the permanent treatment remains clean. 
In speaking of my lime treatment on the principle 
of exhaustion, I mentioned eight weeks as the time 
required for all the spores to come out from first to 
last, but, in giving the duration of my new process 
as of three months or more, I speak advisedly, since 
the two treatments are essentially different in their 
action. By ouiward and direct application, the spores 
are only killed as they make their appearance ; that 
means the spores are all fully developed before acted 
upon, and theiefore the leaves have to empty their 
tissue of all particles of the fungus, which takes from 
7 to 10 weeks, according to the weather. The effects of 
vaporization are quite different, inasmuch as the 
vapor is inhaled through the breathing organs of the 
leaves, and so brought into immediate and deadly 
contact with the mycelia lodged in the cuticle ; sickens 
and weakens them ; and thereby retards and finally 
arrests their development, according to the differ- 
ent age and strength of the pinspots. All tbe 
leaves which bud and form after the establish- • 
ment of my system will mature free of fungus, 
and, under its permanent influence, must remain 
so, no matter how thick the fungus may be in the 
next adjoining field for want of treatment, thereby 
Becuring to any one employing it the full benefit of his 
outlay. My meihorl establishes a deadly enemy to Hemi- 
leia vastatrix, all pervading, ever-present, — nothing can 
escape it, nor is failure possible, except through the 
grossest mismanagement or wilful neglect of one 
operator, who may have as much control over the 
process as it is possible to have of anything. Not any 
part of the plant is injuriously affected through it : 
not even the tenderest flower bud or young leaf. 
