The Redwood gazette. [volume] (Redwood Falls, Minn.) 1873-1940, 1909-04-21

but few people know what
they really are. Although they are
so small that it would take several
thousand together to make a spot
large enough to be seen with the
naked eye, yet their Importance to
the farmer is not measured by their
size
Bacteria are tiny plants, each com
posed of a single cell. These cells
are of various shapes and sizes. Some
are round. some long and some shaped
like corkscrew Some are found
singly and some in groups. Some
cannot move at AT, s6ne move by
twisting themselves about, and still
others have long, tail-like dagella by
which they move themselves along.
Bacteria are made up of a clear,
jellylike material called protoplasm.
This protoplasm is surrounded by
harder cell wall. There is great
difference in the thickness Of these
cell walls. and on this thickness de-
ponds to a large extent the ability of
the germs to withstand unfavorab BILE
conditions. Those with thin cell walls
can be killed easily, while the thicker
walled kinds are very difficult to eX
terminate
Bacteria propagate themselves by
dividing. One cell divides into two
Each of these two grows to full size
and divides again, and SO on. Under
favorable conditions this process may
be repeated every half hour. At this
rate the descendants of one germ
would in ten hours number more than
a million
At times the part of the protoplasm
of germ will gather into a round,
comparati lively hard mass. called Il
spOre The rest of the cell then crum-
bles away. This spore is Inactive but
possesses rouca greater powers Of re-
sistance than when in the active state
These spores often remain alive to
start the infection afresh after the
active bacteria have all been killed by
disinfection.
Bacteria like higher plants, have
definite requirements for growth. One
of the most important of these is mCis-
ture. Drying will not kill bacteria. hut
it will stop their multiplication. An
other essential to bacterial growth is
warmth. Cold. like dryness. will not
kill them. but it will stop them from
multiplying. This is the reason that
the souring of milk or the spelling OF
meat, which is caused by bacteria.
goes on much more slowly or not at
all when they are kept in a cold place
One Of the principal foods of bacte-
ria is nitrogen. Without it they can
not live. Because Of this fact sugar
and lard which contain no nitrogen
never spoil. Bacteria also require oXy-
gen. though only certain species are
dependent on the air for their supply
One of these is the kind that causes
meat and vegetables to decay. This is
why canned fruit and vegeta bles do
not spoil. The bacteria have been
killed and the oxygen driven off by
heating. The few germs that do get in
before the can is sealed up cannot de-
velop for lack Of air. If the can is not
air tight, however. some oxygen will
find its way in, the germs will multi
ply, and the contents will spoil.
Not all bacteria are injurious. AL
though some Of mans most deadly en-
emies are found among these invisible
heterogeneous. yet many of them
are his best friends. We have already
| learned about the bacteria that live on
the roots Of legumes and change the
nitrogen of the air into a form in