The modes of origin of lowest organisms / including a discussion of the experiments of M. Pasteur

by H. Charlton Bastian

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167° F.

No. LXV.

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167° F.

All these solutions remained quite clear and free from any trace of general turbidity for ten days. Each fluid was then inoculated with some living Bacteria, and in the space of thirty-six to seventy-two hours, all had become more or less obviously turbid, and on microscopical examination this turbidity was found in each case to be almost wholly due to the presence of multitudes of Bacteria.

Interpretation of the Experiments: Conclusions as to the Cause of Fermentation, and as to the Occurrence of Archebiosis.

These experiments seem to show quite conclusively that M. Pasteur’s explanations are altogether inadequate to account for the occasional preservation of boiled fluids in bent-neck flasks. They show that the preservation, far from being universal, is only occasional, and that preservation or non-preservation of different fluids is almost wholly dependent upon their nature. They lend no countenance, moreover, to his particular theory, that fermentation cannot be initiated without the agency of living ferments,—they are, on the contrary, wholly opposed to this restriction.

The plug of cotton-wool, or the narrow and bent tube may, it is true, protect the boiled fluid from subsequent contact with living “germs”; but that the fluids do not undergo change on account of such deprivation cannot be safely affirmed, when the same means would also filter from the fluid some of the multitudinous particles of organic matter (dead), which the air undoubtedly contains, and which may act as ferments. It must be remembered that the main object of M. Pasteur’s investigation was to determine whether fermentation took place under the agency of mere dead nitrogenous matter, as Liebig and others affirm; or whether it is only initiated by living organisms, as he himself supposes. Obviously, therefore, the same filtration which purified the air from any living organisms would filter from it its nitrogenous particles, which are the other possible ferments: so that no conclusion could be drawn from such experiments, more favourable to the one than to the other of these hypotheses. All that could have been safely affirmed was, that by boiling the fluid, and then protecting it from subsequent contact with everything that could act as a ferment, fermentation would not take place.

Even this however,—as the preceding experiments fully show—cannot be truly affirmed to be a general rule. Some infusions do undergo change, notwithstanding this treatment and deprivation, whilst others do not: that is to say, some still preserve a first degree of fermentability even after boiling, whilst others are reduced by this process to the second degree of fermentability. These latter are unable to initiate changes by virtue of their own inherent instability; molecular re-arrangements require to be set on foot in them by contact with some more unstable substance, which is itself undergoing change.