principle which could have conducted the antiseptic system to a
successful issue. The strictures regarding defects of reasoning, to
which we have been lately accustomed, throw abundant light upon their
author, but no shade upon Pasteur.

Redi, as we have seen, proved the maggots of putrefying flesh to be
derived from the eggs of flies; Schwann proved putrefaction itself to
be the concomitant of far lower forms of life than those dealt with by
Redi. Our knowledge here, as elsewhere in connection with this
subject, has been vastly extended by Professor Cohn, of Breslau. 'No
putrefaction,' he says, 'can occur in a nitrogenous substance if its
bacteria be destroyed and new ones prevented from entering it.
Putrefaction begins as soon as bacteria, even in the smallest numbers,
are admitted either accidentally or purposely. It progresses in
direct proportion to the multiplication of the bacteria, it is
retarded when they exhibit low vitality, and is stopped by all
influences which either hinder their development or kill them. All
bactericidal media are therefore antiseptic and disinfecting.'
[Footnote: In his last excellent memoir Cohn expresses himself thus:
'Wer noch heut die Faeulniss von einer spontanen Dissociation der
Proteinmolecule, oder von einem unorganisirten Ferment ableitet, oder
gar aus "Stickstoffsplittern" die Balken zur Stuetze seiner
Faeulnisstheorie zu zimmern versucht, hat zuerst den Satz "keine
Faeulniss ohne Bacterium Termo" zu widerlegen.']

It was these organisms acting in wound and abscess which so frequently
converted our hospitals into charnel-houses, and it is their
destruction by the antiseptic system that now renders justifiable
operations which no surgeon would have attempted a few years ago. The
gain is immense--to the practising surgeon as well as to the patient
practised upon. Contrast the anxiety of never feeling sure whether
the most brilliant operation might not be rendered nugatory by the
access of a few particles of unseen hospital dust, with the comfort
derived from the knowledge that all power of mischief on the part of
such dust has been surely and certainly annihilated. But the action
of living _contagia_ extends beyond the domain of the surgeon. The power
of reproduction and indefinite self-multiplication which is
characteristic of living things, coupled with the undeviating fact of
_contagia_ 'breeding true,' has given strength and consistency to a
belief long entertained