5 



water. If this were so, the disease could hardly exist, for where are the trees that are covered with 

 drops of water for forty-eight hours ? Besides, it must be remembered, that during heavy rains no 

 tubes can be formed by the spores, as they would be washed off by the constantly falling drops. The 

 period required, is, however, very much shorter. In a number of trials, the spores germinated after 2 

 hours aud 20 minutes, and a few hours afterwards there were tubes long enough to enter the stomata. 

 Sometimes the operation took a longer time, but whenever the spores were alive the tube was in full 

 growth after five or six hours. 



On examining a coffee bush in the morning after a rainy night, it will be seen that the old leaves 

 are nearly all quite dry, but the freshly unfolded leaves, soft and pale green, still retain on both sides 

 some drops. This is due to their possessing still some of the sticky bud resin which has prevented the 

 fall of the drops. 



From this it appears that the young leaves alone can be attacked by the disease, and this is abso- 

 lutely correct. On each branch the yellow spots first appear on the third pair of leaves, counting the 

 bud as the first pair, for the second pair though probably affected does not show the spot for a month, 

 by which time the next pair of leaves has been unfolded and a new bud is formed. This then is the 

 appearance of a branch. The bud is not affected, the next pair is affected but not visibly, the third pair 

 shows yellow spots, the fourth and lower pairs are more affected not only by the primary but also by 

 the secondary spots. 



Much importance attaches to this observation, for it reduces the treatment of the whole plant for 

 the disease to the treatment of a single pair of leaves upon each branch. If the primitive spots are 

 destroyed on the third pair of leaves, the leaf is safe from further infection. The danger from secondary 

 attacks, the real cause of the fall of the leaf, is thereby removed, and the chance of a renewed attack on 

 the treated leaf is but e mall as the leaves soon pass out of the stage in which, owing to the persistence 

 of the bud resin, the rain drops do not run off- 



The rainy months of 1887 and 1888 confirmed this ; the appearance was as described above with 

 but few exceptions, but in 1889, these exceptions had become the rule. The attack was remarkably 

 heavy, more so than any one in Buitenzorg had ever known before. As a rule, not more than three or 

 four spots occur upon the third pair of leaves, and very often only one or two, for rain drops only remain 

 upon these leaves irregularly and do not cover them. But now nearly all the leaves were covered with 

 sick spots. The opening of the leaf buds which may happen in the West monsoon in Java in twenty- 

 seven days only commenced after long intervals and consequently the latest opened pair on each branch 

 and even the bud leaves shewed the well-known signs. What was the cause of this exceptional attack ? 

 No one in Buitenzorg remembered a West monsoon with so little rain, or with such heavy dews, and 

 the attack is closely connected with the latter. When the dew falls upon a coffee leaf, it does not, like 

 rain, collect in large drops and then fall off, it is deposited in drops so fine that they do not run together. 

 In the morning after a clear night in the rainy season, it is not rare to find a coffee bush covered with 

 dew. If there are spores on the lower side of the leaf either before or during the fall of the dew it is 

 possible for the leaves to be very extensively and completely infected. 



Many planters cannot get rid of the idea that the disease can do no harm on virgin soil or on 

 ground that has been well worked and manured. This is, however, quite erroneous. A badly nourished 

 plant possesses, it is true, little power of resistance when attacked, but the hypothesis that a well nou- 

 rished individual under favourable conditions is less or not at all liable to attack is certainly untenable. 

 Experiment has shown that predisposition to disease or incapacity for receiving it alike do not exist. 

 Liability to sickness is quite independent of the soil, altitude or conditiou of life of the plant. Dr. Burck 

 found the disease at 5,000 feet elevation on the Tengger and other mountains as on the sea coast near 

 Poeyer ani at all intermediate levels. It was as destructive in the well manured and carefully culti- 

 vated gardens of private planters, as in the abandoned plantations of the poorer cultivators, in virgin 

 soil and in ground long under cultivation. All sorts and varieties cultivated in the East Indies, or intro- 

 duced from Brazil, and all the species in cultivation, Ooffea arabica, liberica, benghalensis and Mara- 

 gogipe Coffee, are equally liable to the attacks, nor has a single plant been found that absolutely resists 

 disease. Bushes which planters have affirmed to be disease proof have always taken the disease when 

 inoculated and become sick in the usual period. 



Some planters imagine that the coffee plant may, during lapse of time, have become liable to the 

 attacks from cultivation, and various are the causes to which this is ascribed. Some attribute it to the 

 continuance of long and enforced cultivation ; others to the exhaustion of the surface soil, or to the 

 dampness of the climate. It is quite possible that long cultivation may have had some injurious effect 

 upon the plant. But little attention has been paid to the selection of seed, methods of planting, &c, but 

 whether and in what way these have affected the plant it is difficult to decide. Correct descriptions of 

 the Arabian coffee plant of two centuries ago we do not possess, and cannot compare it with that of the 

 present day so as to know whether it then produced more fruit than now. However, if the soil be suit- 

 able and the plants properly and carefully cultivated, we have no need to complain of the results. Dr. 

 Peilen tells us that the Arabian coffee iu its native home, in Galla country in Abyssinia and at Kaffa, 

 can produce 20 to 25 pounds in its second year. This is indeed hardly credible ; but it is easily conceived 

 that the originally introduced plants might have produced a very much larger crop than most of the 

 trees do now. That the soil in Java has deteriorated through coffee cultivation is true, but that this 

 predisposes the trees to the disease is negatived by the fact that the disease appears as acutely in plants 

 grown in virgin forest ground, well cared for plantations and in pots with carefully prepared soil, as in 

 old ground. 



The suggestion of Dr. Peilen that the relative dampness of the climate has made the plant more 

 subject to hemileia is also highly improbable, because it leads to the belief that the coffee durino- 

 two centuries of cultivation has only just begun to feel the effects of the dampness of the climate. The 



