Wilmington daily commercial., 1874-10-02
wby Eruit Decays-An Interesting Scr-
entIfic Article ON the subject.

entIfic Article ON the subject.
Our worst enemies, says the Scientific Ameri
can, are the smallest. All the ravenous boasts
in the world, mad dogs included, probably de-
stroy fewer human lives than are destroyed in
New York city alone by the ravages of those
minute but virulent organisms of the genus mi
orocoocus to which we owe smallpox, diptheria,
and some other malignant diseases. Similarly,
the thousand sturdy weeds which annoy the far
mer, the caterpillars and grasshoppers which oc-
casionally devour his crops are relatively inno-
cent and harmless compared with the numerous
microscopic pests which rust his grain, rot his
potatoes and fruit, and otherwise levy their bur-
densome taxes without making themselves visi-
BILE.
Just at this season, not the least interesting
of these individually insignificant, collectively
enormous, nuisances are the two forms of fun
gus growth which have most to do with the un-
timely destruction of fruit-nlucor nttcedO and
pendulum gtducum.
Our apples decay, not because it is their nature
to- az Watts might say, but because it is the ma
ture of something else to seize on them for sub
sistence, as we do, at the same time making OF
them HABITAT, as we do not. Kept to them
selves, apples and other fruit never rot ! they
simply loose their juices by evaporation, shrvel,
and become dry and hard, or, kept from drying,
remain substantially unchanged, az when secure
" canned. 1t is only when invaded by the organ.
isms we have named that they loose color and
quality, take on offensive tastes and odors, be-
come covered with white or green mold-in short,
develop rottenness and decay
1t was not until tho microscope was brought
to bear that the real nature OF the process be-
came clear Now We know that 80 far from be-
ing the complement of growth, the antithesis Of
life, decay il in reality the taking ON OF more
rapid though specifically different growth. 1t is
Synonymous not with death, but with intensely
active life.
| lii general structure, tho numerous mrcro-
scopic fungi are very much alike, consisting
mainly of a network OF coorless cells and fila
ments, called the nlyceli,inl. This is the vege-
| tatiye part There is, besides, u produc i've
part, in which is produced tho seed or 'spore,
tho structure of which is different in
the different genera. In the mucor
each productive iilament bears globular swell
ling at its superior extremity, in the interior OF
which the spores are developed. In the pencil
lium glaucum the reproductive filament bears a
tuft of from four to eight branches, which, in
turn, produce upon their extremties u chaplot
OF small oval Spores 1t is called the pendulum
ON account of this pencil-like tuft of its spore-
bearing tilaments, and glluclun from their blush
green tint. The mold 30 frequently seen in
oranges is produced by this fungus. 1t il com
paratively of slow growth, and the alteration il
produces in the properties of the fruit it lives III
and upon ia not 80 marked as that caused by the
mucor.
When the fruit is invaded by either OF these fun
q, the yegetatiyef aments send their branches a
nong and around the fruit cells, and rapidly
envelope them in network OF mycelium, alb
sorbing the substance and juice of the fruit
and producing the chemical transformation
characteristic of decay. All this goes on in the
interior of the fruit the qualification of th'
fungus taking place only Oh the surface, in con
tact with the atmosphere. For this reason fru
covered with a firm, fine skim like the apple
may be mass of what we call corruption within
in other words thoroughly decomposed by fun
gus growth-while no visible mod-the fructi
fying part-appears on the surface. On the 9th
or hand; thin skinned fruits like the strawberry
Il which are easily pierced by the reproductive i'll
aments, are often covered with IN abundan
:, fructification in a very short time, for the fe
cundity of these microscopic cfungi is sometime
u as marvellous as the rapidity of thei
! growth. For example A single zoospore o
N the per0nOspord infesfdno, which causes the po
tato rot, will envelop the cellular tissue OF po
i tato leaf with mycellum iilaments in twelv
o hours, and fructihcation will be completed /
4, eighteen hours longer. One square line of Til
under surface of a leaf, where the fructfcatio
naturally takes place, may bear as many rs thre
= thousand spores. Each spore supplies half
NJ dozen zoospores, individually capable OF orig
mating new mycelium. From one square lln'
therefore, there may come, in less than Nv
-. days, nearly twenty thousand reproductiy
II bodies Il square inch may yield nearly three mi
If lions ! No wonder the disease spreads rapdl
In5the case of fruit decay may be originate
III Two WhNs, anu lWO Only-- Dy ulrecb cOnlablo
-. or by wind waited spores. With firm-slnnc
Y feitiai' namely break iii tho sRrrr' -riorrT
to allow the parasite to enter and take posse
sion. In every case of decay in apples, the Gel
tire Of disturbance will be found at brlis
scratch or puncture and unless such a way !
opened, the apple may hang until it il dry
a leather, or it may lie for weeks in direct cOnta
with rottenness, and remain perfectly sound.
H. To this it may be objected that tile c0nstal
m presence Of the fungus in decay it no proof thl
it IL tho cause Of that condition. OH the contrar
le the breaking down of the fruit tissue by vi
lence, and subsequent chemical action owing
o. access OF ar,may rather make the growth of L
fungus possible by preparing suitable soil (
III its development. The objection has been met
the Investigations of Davaine. The eviden
as that the fungus precedes and CAUSES the chang
which We call decay is of the same character
y, that which establishes the connection between
Ill vaccine pustule and incubation by vaccine viri
sw When sound fruit is inoculated with the spOl
i, of pencilliun, decay begins at and spreads fir
I'LL the point Of incubation. Apples similarly woul
ded, but not noculated, remain the same.
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