The principles of bacteriology : a practical manual for students and physicians / by A.C. Abbott.

  • Abbott, A. C. (Alexander Creever), 1860-1935.
Date:
1896
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Licence: Public Domain Mark

Credit: The principles of bacteriology : a practical manual for students and physicians / by A.C. Abbott. Source: Wellcome Collection.

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    spontaneous generation no longer existed, was met by Spallanzani by gently tapping one of the flasks, that had been boiled, against some hard object untd a mmute crack was produced ; invariably organisms and decompo- sition appeared in the flask thus treated. From the time of the experiments of Spallanzaui until as late as 1836 but little advance was made in the elucidation of this obscure problem. In 1836 Schulze attracted attention to the subject by the convincing nature of his investigations. He showed that if the air which gained access to boiled infusions was robbed of its living organisms by being caused to pass through strong acid or alkaline solutions no de- composition appeared, and living organisms could not be detected in the infusions. Following quickly upon this contribution came Schwann, in 1837, and somewhat later (1854) Schroder and Dusch, with similar results obtained by somewhat different means; Schwann de- prived the air which passed to his infusions of its living particles by passing it through highly-heated tubes; whereas Schroder and Dusch, by means of cotton-wool interposed between the boiled infusion and the outside air, robbed the air passing to the infusions of its organ- isms by the simple process of filtration. In 1860 Hoffmann and in 1861 Chevreul and Pasteur demon- strated that the precautions taken by the preceding in- vestigators for rendering the air which entered these flasks free from bacteria were not necessary; that all that was necessary to prevent the access of bacteria to the infusions in the flasks was to draw out the neck of the flask into a fine tube, bend it down along the side of the flask, and then bend it up again a few inches from its extremity, and leave the mouth open. The