656 
THE TROPICAL 
AGRICULTURIST. [April 1, 1902. 
havo from 1885 to 1888 in Brazil completely destroying 
the plantations in large districts in that country. The 
report draws the foUowiDg analogy between this dis- 
ease and the present out-break at Alexandria :— 
'• The history of the former disease is very interest- 
ing and instructive inasmuch as the disease could be 
traced back to 1869, that is to say to years before the 
cut-break became really serious. Nothing was known 
of the pest nor were any attempts made to cope with it 
until the year 1887, when a surface of about 715,000 
feddana was infected and the cultivation of coffee ren- 
dered impossible. The similarity to the present case is 
striking It has been known for some S or 4 years 
that a banana disease existed in the district around 
Alexandria The disease was first located in a small 
area then at some little distance from the first ob- 
served area, and finally is now spread in the whole 
neighbourhood, it not only infecting plantations but 
has found its way into private gardens. " 
We need not reproduce the first part of the report, 
which is purely technical, but the conclusion, deal- 
ing with the methods of stamping out the disease, de- 
serves to be reproduced in full ;— 
" The most important question to be considered, 
is how to cope with the disease, in other words, how 
to prevent the propagation of the worms. This can 
only be arrivei at through an exact knowledge of 
the life histories of the pests. In order to arrive at 
this an examination at one season of the year will 
not 'suffice, and with the advent of warmer weather 
further observations may be made. It has been seen 
that all the different species pass a certain period of 
their life history outside the plants themselves, that 
is to say in the soil, this being a common feature 
iu the history of all paraaitio animals since it is 
the only means by which they can spread. The 
time therefore, in which to institute an attack is 
when the majority are found in the soil, for any 
attempt to reach the pest when within the plant 
must be doomed to failure, as it is then in perfect 
security In countries where there are well-defaned 
seasons with great difference between them it is 
more easy to ascertain exactly the different stages 
than is the case with such a climate as that at 
Alexandria where probably development goes on 
steadily that is to say, the few worms are always 
present in the soil. It is, on the other hand, also very 
likely that their numbers become considerably in- 
creased at certain periods in connection with the sub- 
sequent generations. Any remedy to be applied would 
therefore have its maximum effect only if applied 
during those periods. This matter can, however, 
only be definitely decided when the life histories of 
the species have been followed throughout. Experi- 
ments could then be conducted as to the most suitable 
means to employ. In coping with nematodes attack- 
ing the beet crop in Germany a method was suc- 
cessfully adopted which may be mentioned here. 
Nematodes are found in, one might say, almost every 
plant in small numbers. Practically all nematodes 
living as parasites on plants are not exclusively 
parasitic on one individual species, for if they find 
the necessary favourable conditions for existence they 
will att ck another host, just as a human being or 
an animal can carry injury to li-alth, and only show 
signs of suffering when the number increases, so 
within certain limits can plants withstand nematodes, 
and only show signs of disease when their numbers 
become excessive. To combat the pest in the sugar 
beet plantations, other plants which were suitable 
ae hosts were used to attract the pest. The seed 
was sown early in spring, some weeks before the 
beet were planted. 
" The larvse of the nematode hibernate freely in 
the soil aud attacked the newly-sown plants which 
were Bubseqnerulv removed and destroyed. There 
were thus removed from the soil vast numbers of 
the pest which would otherwise have attacked the 
beet. This did not result naturally in a complete 
clearance of the beet but ihe numbers remaining, 
the beet were enable to resist. The adoption of this 
method in the case of banaaas would present certain 
modifications but some thing might be done in tbia 
direction and then by providing the plant with suitable 
conditions for recovery i-uch as good cultivation aud 
an application of suitable mR,nure they may recover. 
" The idea has been expressed that the disease is 
one of recent introduction, but this does not seem 
Erobable. Species of the genus heterodera were found 
y Dr. Loos in a garden at Alexandria some years 
since, and these were similar to the heterodera of 
the bananas. It is probable that they have now 
found a most suitable host in bananas and have con- 
sequently rapidly increased in numbers. They have 
probably been living in banana plantations for some 
considerable time and the result of years of increase 
is now very apparent. 
"Experiments in the direction indicated should be 
attempted ; first to ascertain plants met suitable, 
the times at which they should be shown, and the 
time at which they should be removed. The latter 
iuformation could oi course be derived by a study of 
the complete life history of the pests. 
"Various remedies have been suggested in the 
direction of applying to the soil some substance which 
would prove harmful to the pests. We think the 
most suitable substance to try at first is ordinary 
lime. This substance is most commonly applied as 
a remedy for insect pests either alone or mixed with 
common soot. Lime from gas works might also be 
employed. A certain quantity well incorporated with 
the soil around the plants might have a most bene- 
ficial effect, and would probably benefit the crop at 
the same time. It is at any rate a practical and 
inexpensive method. Much has also been said con- 
cerning an application of nitrates and many mis- 
leading and inaccurate figures published regardine; 
the percentage of nitrates present in the soil. We 
do not deny that an application of nitrogenous 
manure may have beneficial effects, not as a direct 
remedy against the pests but merely as encourag- 
ing and stimulating the plant and helping it, provided 
the numbers of nematodes are not too excessive to 
outgrow and overcome attack. 
"Experiments might also show if the worms in 
question or similar ones are capable of attacking 
other and more important crops in the country. 
V/heat and onions are known to suffer occasionally 
by the attacks of nematode worms belonging to the 
genus Zylenchus. The Zylenchns of the onions causes 
great damage in Europe and is found occasionally in 
the crop of Upper Egypt. " — Egyptian Gazette. 
CAMPHOR. 
(Continued from page, 587.) 
PREPARATION OF THE CAUPHOB. 
As soon as the plants have reached a fair size an^ 
formed stout woody stems below — say in three years 
or less in very good situations — they may be clipped. 
The simplest method will perhaps be to use hedge 
shears, placing a long basket below the hedge to oateh 
the clippings. Only the leaves and young twigs are 
required ; woody twigs yield little or no camphor. 
In Japan, where, however, they only use the woods 
of full-grown trees as a source of camphor, the chip 
of wood are distilled in a primitive-looking bat 
effective still, with bamboo tubes (these have the ad- 
vantage that they can afterwards be split to remove 
any camphor from them) and a wooden condenser 
with water running over its lid. In Ceylon probably 
the best method will be to fis up a small still of any 
good pattern with a glass condenser and plentiful 
water supply, working it by means of steam from the 
factory boiler. As the distillation is a somewhat un- 
certain operation, especially to the beginner, and as 
it is probable that more efficient methods will be 
discovered, the details of the principal experiments 
tried, are given below, Material for these experi- 
