574 



THE TROPICAL AGRICULTURIST. 



[January i, 1883, 



experiment. I did that, so that they might prove to 

 themselves, to you and to the reat of your readers, 

 that the disease is uot coutagioua aud that im- 

 poverished soil is also one of the causes. Now, if 

 they like to try another experiment, they will prove 

 the whole cause aud the cure. In this experiment 

 the glass shade is uot required. Fill two pots with 

 gO'id, rich soil, and in each pot plant a diseased 

 plant ; cover the soil of one pot with a carpet of 

 dry moss or dried grass, so that it will shade the 

 soil WELL ; then water freely (taking care not to put 

 too much water aud so wash the goodness of the 

 soil : through ihe holes in the bottom of the pot, 

 as then the plant would suffer from impoverished 

 soil) watch which plant recoverB first. When both 

 plants Lave recovered, slop watering for three or four 

 days ; then water one day and stop watering for 

 three or four days and so on and see which plant 

 becomes diseased. The stopping of the watering must 

 be done in hot dry weather and both pots should 

 be kept in the open. — Yours truly, 



6. F. HALLILEY. 



GOOD RETURNS OF BARK FROM 

 C. OFFICINALIS. 



Dikoya, 7th Deo. 18S2. 

 Dear Sir, — We have been favored in your columns 

 with the outturns of bark from giant succirubra trees, 

 but I do not remember to have seen any record 

 of returns from officinalis. 



It may therefore interest those who are sceptical 

 as to remuneraiive returns from this variety 

 planted through coffee in a wet district, to learn 

 that twenty-seven lbs (27) of spoke shavings were 

 taken lately fr.im a pure officinalis trees. These dried 

 down to a Uttle overS lb.— Faithfully yours. 



CROWN BARK. 



LEAVES AND LEAF-DISEASE: EFFECTS OF 

 CARBOLIC ACID. 

 Claverton, Dikoya, 9th December 1882. 

 Dear Sir, — " W." in the long and able letter which 

 you published last Tuesday, has forged a new argumen 

 against the leaf-disease theory which the seekers after 

 liyht would do well to look into. He cites the de- 

 privation of foliage by pruning, etc. (the effect of 

 which is only to do gciod) as a re.a3on for supposing 

 that the somewhat similar action of the lungus 

 cannot do harm. I say somewhat similar, because it 

 may fairly be doubted whether there is any real 

 analogy between the taking-ott'ol supeiabundaut young 

 or old branches (not leaves mark you) by the kmfe 

 or hand aud the depriving of the branches which 

 we purp>iselj leave on for fruit of their sustaining 

 leaves. To test "W."'s argument fairly, we must 

 compare the loss of leaf simple by the action of the 

 funuus with a corresponding loss of leaf simple from 

 other causes, let us say from wind, and I think 

 tiapuiale planters will tell us th.it tfle latter does 

 not necessarily result as is the case from leaf-disease 

 in failure of blossom. Far be it from me to suggest any 

 ciiptious criticism on " VV." 's well-reaeoned theory, 

 only let us beware of fallacies and that we hive one 

 hen I have a shrewd suspicion from the way in 

 which " VV. " goes on to instance Dr. Trimeu's re- 

 marks on the gum disease "were the leaf and spots the 

 whole mischief not much harm would be done." 'W." 

 contends that in coffee the loss of leaf is the sole 

 mischief and he no doubt is here shielding himself 

 in the robur et as triplex of the doctrine of the 

 scientists who deny that the fungus affects the 

 coubtitution of the coffee tree, for he further slates 

 th.a the tine flushes produced after le;if-disease 

 attain a luxurious growth until attacked from icitliout . 



Doubtless in exceptionally vigorous and highly manured 

 coffee this is to a certain extent true bat that this 

 is due to the reserve vigour in the tree (probablj 

 enhanced hy the absence of crop) is shewn by the 

 contrary result in weak coffee which can only throw 

 out thin and of their very nature barren branches. 

 Does not in like manner the cankered cinchona stock 

 send up an equally delusive sucker ? I venture to 

 otter these suggestions because it appears to be the 

 dictum of the scientists thai the fungus does not affect 

 the coffee tree constitutionally, and since Dr. Trimen 

 admits such to be the result from the eucalyptus 

 fungus, it would be as well to know why a similar 

 though perhaps less immediately fatal result may not 

 be attributed to the Hemileia ? The aBSumptiou that 

 it is not so may, I believe, be fairly credited to 

 Dr. Hooker who in replying to the enquiry of Go- 

 vernment as to the policy of spending money on a 

 cure for leaf-disease stated that the fungus 

 was not a disease at all, but merely a parasite which 

 jeeds on the leaves of the coffee and consequently 

 that it was absurd to spend money on curing a 

 disease which did not exist. It appeared to me at the 

 time thatthis was a very official, not to si.y evasive.way of 

 dealing with queslion and I hardly knew whether to be 

 more surprized at such a reply emanating from so 

 high an aulhority than at the meek way in which 

 the Planters' Association appears to have accepted 

 it as final. Now, sir. I leave it to Dr. Trimen to 

 explain to us the distinction between the fungus* 

 which affects the constitution of the eucalyptus through 

 its leaves and a somewliat similar fundus which, so 

 far as we cau judge, renders our coffee barren. Are 

 they not both correctly to be termed diseases, and is 

 not a fungnid growth on plants analogous in ils bear- 

 ings to parasitic attacks in the annimal world, such, for 

 in.itauce, as tubercles in the lungs of a man in 

 consumption? If the latter is admitted to be a disease, 

 why are we by a few strokes of Dr. Hooker's pen 

 to be denied the assistance of Government in seeking 

 a cure for what is equally a disease in our coffee? 

 I should not have ventured into your columns merely 

 to air any unscientific views of my own, were I not 

 also engaged in conjunction wiih other Dikoya planters 

 in testing the effect of carbolic on 100 acres on this 

 estate, and it is as much owing to the develop:iient 

 of a new phase in this as to " W'.'s letter that I 

 now write to you. I may here state that all who have 

 been connected with the cultivation here during the 

 experiments, from my assistant and myself to my coolies 

 anil kanganies (the latter of whom began by dis- 

 believing in it, having, they said, seen it fail iu Dim- 

 bula) are firmly convinced that the carbolic does 

 kill the fungus. The Dikoya Committee decline at 

 present to give an opinion on what I consider 

 to he very good grounds, tnat even, supposing leaf- 

 disease to be cured, the real object in viuw namely 

 the securing of increased crop cannot be ascertained 

 until the next blossoming season is over, ihe coffee 

 has been unusually free of disease while under the 

 treatment v/hich came to an end by my running out 

 of powder ab.ut 15th November last. Since then there 

 has been a very considerable fall of leaf, and it might 

 be supposed by believers in the carbolic that this wns 

 the natural result of its cessation, i cannot attri- 

 bute it to this cause innsmnch as there is little or 

 no evidence in the fallen leaves of disease in any 

 form. I consider it arises entirely from other causes 

 but am far from thinking the fall of leaf a natural 

 oue. It is this fact that above all others suppons me 

 iu my belief that the fungus has affected the consti- 

 tution of the tree itself, and that the character of 

 the leat now produced, even where leaf-disease ia 

 absent, is of a weakly and deteriorated type, the 

 result of constant efforts ma de by the trees of late 

 *See Dr, Trimeu's letter on next page.— IfiD, 



