224 
THE TROPICAL AGRICULTURIST. 
[August r, 1881, 
is rather far-fetched and indeed absurd. It is a rather 
common belief now that some of the gum trees of 
Australia, notably the blue gum. have similar pro- 
perties, but the more reasonable explanation is that 
these eucalypti are capable of absorbing the moisture 
and drying up swamps in which they are planted 
and consequently of absorbing and dissipating malaria. 
Very probably the Eucalyptus rostrata may be use- 
ful in this respect. On the other hand, dense shade 
and superabundant vegetation in the tropics conduce 
to fever and other disease; moderate shade is desirable, 
and under the circumstances we have referred to as 
well a9 other peculiar conditions, the planting of 
deciduous neem trees and species of eucalyptus may 
be very beneficial. 
COFFEE PLANT DISEASES. 
[From our London Correspondent.) 
At, last I am able to send you by this mail the 
copy of the Linnean Society's journal for the present 
month, which contains Dr Cooke's and Mr. Bidie's com- 
munications to that Society on the subject of coffee 
leaf disease. Dr. Cooke's paper was, as you will see 
principally relative to that form of it which has made 
its appearance in South America; but I have been 
unable by my perusal of it to decide whether the 
fungi described by him have any connection with 
that, which you referred to me a short time back as 
having made its appearance on the Guatemala 
plantations. Dr. Cooke has described one species 
which is said to have a stroDg phosphorescent 
smell, and it may be that the taint of sulphur 
which the Guatemala disease was said to give 
out is identical with it. If that be so, we might 
be justified in coming to the conclusion that some 
degree of identity was established by the fact, but 
I have not as yet been able to ascertain Dr. 
Cooke s views on this point. I fear his paper is too 
scientific for me to be able to discuss it here, but 
it is a new feature, as far as my experience or read- 
ing goes, to learn from it that the coffee leaf disease 
is, hid gmeris, identical to a great extent in all its 
forms, and that it is only by the different form of 
fungus which it developes that its various classifica- 
tions can be determined. I am glad to see that the 
learned author considers — as he states— that " we are 
now in a fair way cf knowing all that can be known 
of its life history : and this is the only safe basis 
on. which to hope for a radical cure." The deter- 
mination of the last appears, however, to be at present 
as far off as ever ; though the disease in Mysore 
appears to have engaged Dr. Cooke's active investiga- 
black rot" and states it to be unknown in Ceylon, 
giving that special form the scientific nomenclature 
of Pellicularia Koleroga. It was in the year above 
named, 1873, he states, that the existence of destruct- 
ive parasites on coffee became apparent in South 
America, and primarily in Venezuela. The varieties 
of the disease named by Dr. Co ike se^m to be legion 
in number, and all of them, though having the same 
basis, and due probably to the same cause, possess 
distinctive features, as I have said, in the charac- 
ter of the resulting fungus : it being ascertained 
during 1877 that in South America alone there 
were tlv-ee distinctive classifications of the dis- 
ease, one at all events being identical with 
the so-called "black rot" of Mysore. The Com- 
missioner of Agriculture at Bogota d senbed this 
particular form of fungus as having a phosphoric, smell 
and as emitting phosphorescent light at night. It 
Was snid by him to occur more frequently in 
a, imp places than in dry ones, and to show its rav- 
ages mo»t severely in iooaiiti*8 where ihe breed were i 
Closely planted together. It also attacked the trees 
grown to afford shade to the coffee bushes. Further | 
on in the paper, Dr. Cooke affirmed that the disease 
may exist without any visible fungus upon the leaves 
and exhibit no trace of mycelium in the tissues. 
Altogether, he considers the disease to be a complic- 
ated one, and he is not p-epared to state its cause. 
Leaves forwarded to him by Mr. Morris from Jamaica 
showed an entire ly distinctform of the disease from 
tho'e he had previouly known, and he classifies it 
under the title of Cercospora coffcicola. The localiza- 
tion of this form in one particular locality renders it 
still more difficult, Dr. Cooke writes, to answer the 
question : "What is the cause of this form of effee 
disease ?" A plate accompanies the paper, which gives 
illustrative magnified details of the disease of South 
America. Mr. Bidie's remarks on this subj et are 
embodied in a letter addressed by him to Mr. John 
Cameron, the Superintendent of the Botanic Gardens 
at Bangalore, who communicated it to the Linnean 
Society, and they have reference to the form of the 
disease prevalent in Coorg. It was only developed 
there some four or five years ago, and Mr. Came- 
ron thinks it was imported from Ceylon, or from a 
coffee district in Mysore, bearing the euphonious 
name of " Chickmoogloor," the latter place being only 
sixty miles distant from the plantations of Coorg. It will 
be useless for me to enter upon Mr. Bidie's re- 
marks. They appear to me to be pretty identical 
with what I have previously read in your columns; 
but I cannot pretend to eay that they may not 
embody some new points of interest to those better 
acquainted with the subject than I can possibly be a 
from my rather cursory reading respecting it. 
A NEW MAURITIAN INDUSTRY :— FISH 
MANURE. 
The Mauritius Mercantile Revi'w publishes a report 
on a new industry lately started by Mr. Bernard with 
the assi-tance of several Mauritian planters, viz., that 
of making manure from the fish caught at the shoal 
of Saj'a de Maiha, the most extensive in the Indian seas. 
On April 7th last, Mr. Bernard freighted a vessel, 
the "Rodolphe" and sailed from Mauritius, reaching 
the shoal on the 14th. The shoal is about 200 miles 
long and 15 miles in average breadth, situated be- 
tween 56° and 60° E. long., and 9° and 11° S. lat. 
Over the whole extent cf this submarine ban.': of s ic& 
coral, and seaweed, the depth varies from 12 to 15 
fathoms. On account of the shallowness of the water, 
the fish were caught with the greatest facility. The 
shoal covers an area of more than 2,000 square miles, 
about five times the siz^ of the Mauritius, over the 
whoi" or which Hsu. exjsl in such quantities thai) cuey 
may be sail to be inexhaustible. 
Mr. Bernard fished with lines, and scarcely were the 
lines cast into the water, when fish were caught varying 
in weight from 2 to 3 lb. Sharks and other larae 
fish were taken occasionally. In fourteen days' fish- 
ing ten men filled I20ca ks, each containing 3201b. 
of fish or au .average of 3001b. of fish for each mt.ii per 
day. No nets were used, and the work was carried on 
during the whole iime under every disadvantage. The 
fishing hooks were all too small. On this account four- 
fifths of the sharks, which might, have been caught with 
proper hooks, were lost. Notwithstanding that cir- 
cnm tance, 25 or 30 shaiks were taken every day. 
300 lb. of fresh fish represent 100 lb. of dry fish manure, 
containing 11 or percent, of azote, under the form of 
organic matter in close combinatoin with phosphates 
entirely assimilable Mr. Bernard calculates that the 
cost of the manure ready for sale will be less than §aQ 
per ton. Ho assorts ih it boats fo>* fishing purposes are 
far better than small vessels, oa account of the greater 
fac ; iity iu drawing the fish out of the water. Fishing 
operations can be carried on during eight months of 
the year, from September to May. In June, July, 
