Daily independent. [volume] (Elko, Nev.) 188?-1915, 1890-01-24
MODERN BAcrERIoLoax.


What scasnsS KAows About tho "Motes
That Pbople the sunbesm."
Our knowledge in no department Of
science han made greater strides during
the last few years than in that of bac-
teriOlogys The existence Of organisms
Tar smaller than any thing that the
naked eye can discern was, says Cham
bers' Journal, fact little suspected
until comparatively recent times; and
ever since the microscope first revealed
to our eyes the world Of "the infinitely
little," as it has been felicitously
called, our knowledge Of these microscop-
&c forms Of life has gone on increasing.
These heterogeneous exist in the
atmosphere and inwAter; but it is only
within the last few years that we have
had any means Of arriving at an approx
innate idea of the extent to which they
are present in these media. It is in the
first instance to the brilliant investiga-
tions of M. Pasteur that we owe our
knowledge on this point; and the i'm
portant experiments he was the first to
carry out have been developed
and extended by others. Prof. Tyn-
dali has shown that in calm air q
rapid subsistence of these microbes takes
place. The distinguished German
Psychologist, DR.. Koch, has devised
method by means of which we are
enabled to form an estimate of the num-
Der Of these micro Organisms present in
measured Quantity Of either water or
air. The method consists in cultivating
: the germs in q solid medium (gelatine
is most commonly used). Each organism
thus grows and multiplies on the spot
where it is planted, as it is prevented
from moving. The progeny of each
micro-organism in this way gather
round the parental home, and we have
In the course of short time, instead of
the single organism, large colony.
Some interesting experiments were
made on this point short time ago by
DR.. p. F. Frankland.r The air was tested
mt different places and under different
circumstances. 1t was found that the
number OF organisms present in the at
mosphere differed at different seasons Of
the year, the, largest proportion being
found during the summer months: In
certain volume Of air 1.-TWO gallons) col
looted on the top Of the Science and Art
Department buildings at South Ken
sington, one hundred and Ave of these
!, :, micro"organisms were found to be pres
I emit. -s,-.. .... =,
~ So much for the living organisms in
our atmosphere; now for a word or two
on the dead inorganic PARTICLES in the
air. These are infinitely moro aumor.
GUS than the living germs; and an ex-
tremely ingenious method has recently
been. devised by Mr.. John Aitken.
F. r. 8. E., for the purpose Of estimating
their humber: Like the organic germs,
they are infinitely minute in size, most
OF them being altogether unuetected by
the most powerful microscope. It was
necessary, therefore, to have recourse
TO some method Of making them visible.
The plan adopted was as follows: The
air TO be tested was admitted into q
large glass vessel, where it was satu-
: rated with waeer-Vapor; then supersatu-
rated by slightly expanding it by means
s2f an air-pump. The result was fog;
: and as 1t is known that a fog is caused
by those dust-particles becoming sur
rounded by watery envelope, the num-
Der OF fog-particles shows the number
Of dust-particles. The counting of
these tog-particles was effected in the
O"AhS "oJ' "A worry bndll pOrGlOn OF
the air to DO tested was mixed with
large quantity Of air which had been
rendered absolutely pure by filtering it
through cottonwood. The mixture was
then admitted into large glass re-
cetyer and saturated as above described.
AS the dust-particles were so few, in
stead OF fog small miniature rain
was formed, and the number Of these
small raindrops falling on small silver
mirror was counted, and, by a simple
calculation, the amount in the quantity
OF air originally admitted thus esti-
mated. The following are some results
obtained: 1t was found that the air out
side during rain contained per cubic
inch 521, 200 dustparticles; that during
fair weather tho number present was
more than four times that amount:
while inside room near the ceilinp az