Evening star. [volume] (Washington, D.C.) 1854-1972, 1884-08-23
The Germ Theory of Disease.


Let us briefly sum up what is at present
known about the germ theory Of disease. EX-
periments having shown that no life is known
to spring from inauimate matter We may rea-
sonably conclude that just as wheat does not
grow except from seed so no disease occurs
without some disease germ to produce it. Then
again, we may take it for certain that each dis
ease is due to the development of particular
kind of germ. Ii we plant smallpox germs we
do not reap a crop Of scarlatina or measles; but
just as wheat springs from wheat each disease
has its own distinctive germs. Each comes from
a parent stock, and has existed somewhere pre-
viously. 1t is true that complications occur
several diseases running their course at one
time, or one after the other; but however I'M
common, none of them are new. After forest
is cut down new variety of trees may spring
up: but nobody supposes them to have grown
spontaneously. The seeds existed there before
and their growth was due to the occurrence of
conditions favorable to their development. So
the disease germs which are always floating
about may frequently be introduced into our
bodies; but it is only when they meet with
suitable conditions that they take root and
produce disease. Under ordinary circum-
stances these germs, though nearly al
ways present, are comparatively few in
number, and in an extremely dry and indurated
state. Thus, they may frequently enter our
bodies without meeting with the conditions es-
sential to their growth: for experiments have
shown that it Is very difficult to mOisten them.
and till they are moistened they do not begin to
develop. In healthy system they remain in
active But anything tending to weaken or
impair the bodily organs furnishes favorable
conditions, and thus epidemicS almost always
originate aud are most fatal In those quarters
of our great cities where dirt. squalor and foul
air render sound health almost an mpossblity.
Thus, too. armies suddenly transferred from
the regularity and comparative comfort Of bar
rack life to the dangers, toll and exposure Of
the battlefield and the trenches are often at
tackled by epidemirs. Having once got be-
ginning. epidemcs rapidly spread. The germs
are then sent into the air in great numbers and
in moist state and the probabilities of their
entering and Of their establishing themselves
even in healthy bodies are vastly increased.
For the same reasons one disease not I'M
frequently follows another The latter is COM
monty said to have changed" into the former;
but probably the two are entirely distinct. the
second being simply due to the weakening OF
the system.
Another widespread belief is that foul smells
give rise to disease 1t is not, strictly speaking
the foul gases, but the germs present in them,
that produce the diseases. The effiuvia, how
ever, are themselves injurious to health. while
they are indications of state of matters much
more dangerous; and it is never sufficient to de-
strOy evil odors without searching out and re-
moving the causes that produce them.
Climate and the weather have also much in
ffuence on the vitality of these germs Cold is
a preventive against some diseases. heat against
Others. But we have still much to learn regard
ing their behavior under varying conditions.
Tyndal found that sunlight greatly retarded
and sometimes entirely prevented putrefaction;
while dirt is always favorable to the growth and
development of the germs Sunshine and
cleanliness are undoubtedly the best and cheap
est preventives against disease.