January 2, 1882.] THE TROPICAL AGRICULTURIST. 
^55 
I have two Liberian trees to show : one among a 
cluster of five, tho other in a batch of forty home 
distance oft', which were infected at the same time 
as the nursery was. Through my treatment I com- 
ot them 
300,000 
condary 
permanent vaporization 
a district, I venture lo 
jmonth, the chances of 
ified, that the treatment 
ou 
and air carrying the v 
by turns in every direc 
Wherever my method 
will have become gen< 
predict that, after a 
reinfection will be so : 
may be safely discontinued and only taken up again 
for a few months, in the event of local reinfection, 
from the selfsown cofiee in the forest, a native garden 
patch, or through the intercourse of travel by accid- 
ent from a distance. Your planters should endeavor 
areas under regular cultivation. In the event of 
such reinfection, treatment must again be started rit 
• ; secondary 
nil. 
ista 
se from the coll'ee tree, as well as all vegetable 
nsh in particular. — I remain, sir, yours obediently, 
JACOB P. STORCK. 
"GERMS" AND DISEASE IN PLANTS. 
[Gardeners' Chronicle, 5th November 1881.) 
In our last issue, we alluded at some length to the 
action of " Germs " in producing certain forms of disease 
in animals and plants. We showed how modern investi- 
gation had sufficed not only to detect the goims, but 
even to isolato them and prow them under artificial con- 
ditions. The existence of these organisms has, of course, 
been known from the time people began to use the 
microscope ; but it is oidy lately that it has been proved 
that they aro not tho mere accompaniments' of disease 
and decay, but, in some eases at least, the actual cause. 
This has been proved by isolating the genus, cultivat- 
ing them, and inoculating healthy animals with them, 
as detailed in our last number. Introduce theso organ- 
isms, and disease and decay set in ; prevent thoir in- 
gress or destroy them by carbolic acid or other germ 
destroyer, and no disease is produced. Already, in the 
ea r of animal.'., the praelie.d iv.-ult.-, of these diseoveries 
may be called enormous, and the prospects for the 
future aro even mole hopeful. We refer to the subject 
again, because, since writing our remarks, some papers 
of Professor Bnrrill have come under our notico, in whioh 
the author shows that the "blight" in pear and apple 
trees and the "yellows" of the peach owe their origin 
t<< the presence of bacteria. We have ourselves noticed 
the occasional presence of "micrococci" in cankered 
BTipli , but we had looked upon their pre-cnee more in 
tbe li -III of a coincidence than a cause. With Professor 
Bun-ill's papers before us, however, we would urge those 
who have the rcqui ito leisure to investigate thi„ matter 
for IhoniHolves. According to Professor Hun-ill's state- 
nients ha finds bacteria in the drops of whiti.h Hbofo 
fluid found oozing from the bark of disensed apple and 
pear trees. At the same lime the cells of the bark, 
which should be full of starch, are nearly void of that 
reserve of nutriment. The bacteria aro found, as we 
understand it, actually in the cells, but how they gain 
access to the interior is not made out. Inoculation of 
previously healthy trees was practised in a great num- 
ber of instances, the disease being thus reproduced in 
a large percentage of cases, but not invariably. Actual 
inoculation by means of a needle charged with the virus, 
as in the case of vaccine lymph, is necessary, or the 
transfer of a portion of infected bark, as in the opera- 
tion of budding are requisite, as it seems that the 
mere deposit of the virus by means of a brush upon 
the leaves is inefficacious. The progress of the disease 
is very uncertain and inegular, but always slow, no change 
being visible for nine or ten days. The chemical changes 
produced are the giving off of carbonic acid gas and the 
formation of butyric acid. In the Lombardy Poplar these 
ferment-producing agents follow the attacks of the wood- 
boring beetles, and complete the destruction set up by them. 
Such in brief outline are the results obtained by Prof. 
Burrill. We do not know by actual observation what 
the "fire blight" of the pear and the "twig blight" 
of the American apple are, and what relation they hear 
to the canker and other diseases of our fruit trees, but 
wo have said enough wc hope to induce those with the 
requisite leisure and competence to investigate these 
matters for themselves. It may be requisite to point 
out that some only — not all such diseases — are likely 
to be caused by these organisms, that the presence of 
bacteria, micrococci, and the bice need not necessarily 
cause diseased action, for assuredly they often occur 
I where no ill effect is perceptible. Their presence is 
readily detected by the microscopist, but to prove that 
they are the actual causo of the disease requires pro- 
longed careful experiments directly to prove and indi- 
| rectly to show that no other cause is sufficient. Should 
it turn out — as we strongly suspect it will — that some 
forms of canker are due to these organisms, we may 
have a chance of combating the malady by cutting away 
and destroying the affected branches, and by the free 
use of carbolic acid as a poison to, tbe germs. 
A trial might be made of this substance at once, 
for in any case it would be as efficacious as any other 
remedy, and there is the probability that it may prove 
much more so. Practical points to be borne in mind 
are to take care not to take grafts from an affected 
tree, and not to use the same knife for pruning healthy 
trees as has been used for those that are in any way 
diseased. Who knows but that the explanation of the 
facts attributed by some to wearing out and degenera- 
tion of particular varieties may really be due to tHe disse- 
mination of disease by means of the knife and pruning-saw. 
The whole subject demands the most careful examina- 
tion — practical meu are too busy ; few of us, indeed, 
have the requisite leisure, and unfortunately at present 
we have no schools of gardening or forestry, no experi- 
mental botanic gardens where such experiments could ho 
undertaken by competent persons. Some day, perhaps, 
wo shall be wiser. At present not only tho Americans 
but the Germans and the Belgians, and to some extent 
tho French, give us the go-by in these matters, to our 
certain loss in the future. 
Fiji : The Coffee-leak Disease. — With reference to 
the ciu'O described by Mr. Jacob P. Storck, Upper Rewa, 
in the Fiji Time* of tith August, the Gardener? Chronicle 
say.-: "We should be glad to have the testimony of 
some disinterested person on this matter, and some fur- 
ther explanation of the method adopted. - l-'.i s. 
Cockroaches. — Wo would recommend 0. Orpct. tireii- 
eester. to prepare a mixture of oatmeal and plaster of 
Paris in equal quantities with sufficient water to mnkt 
it adhere, dropping it in small quantities in different 
parts of the llexir or stokehole, where the cockroaches 
frequent. W. believe with this method he will soon relieve 
himself of this disagreeable |x.st.— H.uuilsoS A Som, 
Leicester. — Ibid. 
