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fourth series of experiments, in which, previous to forcing
in the air, he permitted the flasks to cool. Into four bottles
thus treated he forced prepared air, and after a time found
fungi in all of them. What is his conclusion? Not that
the boiling hot liquid employed in his first experiments had
destroyed such germs as had run the gantlet of his ap‘
paratus; but that air which, previous to being sealed up,
had been exposed to a temperature of 212° is too rare to
support life. This conclusion is so remarkable that it ought
to be stated in Dr. Bennett’s own words: “It may be
easily conceived that air subjected to a boiling temperature
is so expanded as scarcely to merit the name of air, and
that it is more or less unfit for the purpose of sustaining
animal or vegetable life.”

N ow numerical data are attainable here, and, as a
matter of fact, I live and flourish for a considerable portion
of each year in air of less density than that ’which Dr.
Bennett describes as scarcely meriting the name of air;
the Swiss men, women, children, flocks, herds, tadpoles,
grasshoppers, flowers, and grasses, do the same, while the
chamoisrears its kids in air rarer still.

In a fifth series of experiments sixteen bottles were
filled with infusions. Into four of them, while cold, or-
dinary unheated and unsifted air was pumped. In these
four bottles fungi were developed. Into four other bottles,
containing a boiling infusion, ordinary air was also pumped
——no fungi were here developed. Into four other bottles
containing an effusion which had been boiled and permitted
to cool, sifted air was pumped—no fungi were developed.
Finally, into four bottles containing a boiling infusion,
sifted air was, pumped—n0 fungi were developed. Only,
therefore, in the four cases where the infusions were cold
infusions, and the air ordinary air, did fungi appear.

Dr. Bennett does not draw from these experiments the
conclusion to which they so obviously point. On them, on

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