atoms in the form of carbonic-acid and alcohol,
thus effecting fermentation; it is another microscopic plant--a
bacterium, as Devaine had christened it--which in a similar way effects
the destruction of organic molecules, producing the condition which we
call putrefaction. Pasteur showed, to the amazement of biologists, that
there are certain forms of these bacteria which secure the oxygen which
all organic life requires, not from the air, but by breaking up unstable
molecules in which oxygen is combined; that putrefaction, in short, has
its foundation in the activities of these so-called anaerobic bacteria.

In a word, Pasteur showed that all the many familiar processes of the
decay of organic tissues are, in effect, forms of fermentation, and
would not take place at all except for the presence of the living
micro-organisms. A piece of meat, for example, suspended in an
atmosphere free from germs, will dry up gradually, without the slightest
sign of putrefaction, regardless of the temperature or other conditions
to which it may have been subjected. Let us witness one or two series of
these experiments as presented by Pasteur himself in one of his numerous
papers before the Academy of Sciences.

EXPERIMENTS WITH GRAPE SUGAR

"In the course of the discussion which took place before the Academy
upon the subject of the generation of ferments properly so-called, there
was a good deal said about that of wine, the oldest fermentation known.
On this account I decided to disprove the theory of M. Fremy by a
decisive experiment bearing solely upon the juice of grapes.

"I prepared forty flasks of a capacity of from two hundred and fifty to
three hundred cubic centimetres and filled them half full with filtered
grape-must, perfectly clear, and which, as is the case of all acidulated
liquids that have been boiled for a few seconds, remains uncontaminated
although the curved neck of the flask containing them remain constantly
open during several months or years.

"In a small quantity of water I washed a part of a bunch of grapes, the
grapes and the stalks together, and the stalks separately. This
washing was easily done by means of a small badger's-hair brush. The
washing-water collected the dust upon the surface of the grapes and the
stalks, and it was easily shown under the microscope that this water
held in suspension a multitude of minute organisms closely resembling
either fungoid spores, or those of alcoholic Yeast, or