1 Apri, 1898.] QUEENSLAND AGRICULTURAL JOURNAL. 303 
must be. If the pores of your own skin were closed, you could not live 
twenty-four hours. ‘The breathing-pores which are closed are always, as has 
been said, on the lower side of the coffee leaf; and when the tiny bunches of 
spore-cases are first pushed through the pore, there is noticeable a pale spot 
easily discernible against the light. This spreads like those rings of green 
grass which you see in the paddocks, called fairy rings in the old country. The 
two cases are exactly parallel. They are due to the growth of the spores of a 
fungus in each case. Now the little spot on the back of the coffee leaf gets: 
yellow, and finaliy, as it grows larger, becomes a reddish-orange. The central 
spot becomes dark, because careful Nature, who wastes nothing, chooses that 
spot as the growing place of an Aspergillus, one of the forms assumed by a genus 
of fungi called Hrysiphe. This characteristic appearance is shown upon a 
portion of the leaf at the bottom of the illustration, and the tufts of sporanges 
are shown growing through the breathing-pores in the top left-hand corner. 
The spores which are borne in those clusters of spore-cases are small. You 
can place twenty millions of them side by side on a penny postage stamp with 
room to spare. Fern spores were thonght so small as to convey the idea of 
invisibility, but they are large compared to these. A practical Ceylon planter 
says of them: “A sucker growing from an old coffee stump can produce 
germs enough to inoculate a continent.” In Ceylon and other countries they 
are spread by the wind, by birds, by the fur of animals, and by the clothes, 
skin, and hair of man. 
Quite recently a gentleman from Southern India and Ceylon was examin- 
ing our plantations. He was fresh from Hemileia-infested districts. We 
have seen that the spores can be sent in a letter, and will germinate after 
having been half round the world. Is there any guarantee that there were 
no spores attached to the clothes, &c., of the gentleman referred to, and left 
amongst our coffee. The spores are an impalpable dust, lable to be carried 
in any merchandise—such, for instance, as the coffee imported for our break- 
fast tables in such quantity. It may be well not to dwell in too deep a sense 
of security in quarantine regulations, but to be wideawake for any sign of this 
pestiferous little plant; and to so order things that it will find it difficult to 
obtain a foothold even if the spores do come. } 
_ Coffee was grown in Ceylon for about 200 years, and on an extensive 
scale for forty years, before the coffee-leaf disease was heard of. Then it 
seemed to drop, as it were, from the clouds. About 1,000 species of Ceylon 
fungi had been examined by Berkeley and Broome, but this fungus was found 
‘on no other tree, and never before it was sent by Dr. Thwaites. Yet it must 
have existed. Thwaites believed it to be indigenous to Ceylon. 
We have about ninety plants of the same natural family as the coffee 
growing wild in Queensland. Have they no parasitic fungi biding their time 
until the coffee is in a fit condition to become their hosts? Some of the best 
writers on tropical products have said that good cultivation is the most potent 
factor in disease resistance. The sickly plant is ever the prey to parasites. 
Tt often happens that plants introduced to.a new country make astounding 
growth for a time, far beyond anything they had exhibited in their native 
countries (or the countries in which they were last commonly found). Witness 
‘many of our weeds. But after a time matters readjust themselves. The soil 
becomes exhausted of the constituent required by a particular plant, or some 
other change takes place. Then comes the chance of the parasite, and either 
some native fungus, deprived perhaps of its proper sphere of action by the 
clearing necessary to make room for the newcomer, or some imported fungus, 
takes hold of the enervated plant and works havoc. 
The coffee-leaf disease is not now nearly so dreaded in Ceylon as it 
formerly was; but this is due not to applications of fungicides, which on such 
a scale would be out of the question, but to improved cultivation and to the 
fact that the fungus in its turn does not now find the same growth conditions 
that it formerly did. Last year a large Ceylon estate “topped the record” 
for coffee yield—vide Tropical Agriculturist, Colombo, February, 1878, page 524. 
