Bacteria, the smallest of living organisms / by Ferdinand Cohn ; translated by Charles S. Dolley.

  • Ferdinand Cohn
Date:
1881
Catalogue details

Licence: Public Domain Mark

Credit: Bacteria, the smallest of living organisms / by Ferdinand Cohn ; translated by Charles S. Dolley. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    paniere of decay, and the putrefaction of dead bodies must take place under special conditions, therefore, even if bacteria are kept away. These conditions are not easily obtained if we wish to try experiments in order to prove the truth of this supposition. If for example we place a piece or some of the juice of an animal or plant, flesh, blood, urine, leaves, fruit or seeds in a small glass flask, it is most probable that a few of the extraordinarily wide spread bacteria would be placed in with it, and this supposition becomes almost a certainty if we add anj water to the flask. It requires but a simple means to banish all the bacteria from the flask by cooking the same for a long time. Bacteria withstand boiling heat as little as other plants and animals ; recent experi- ments have even shown that bacteria are killed by a temperature of 60° C., only the temperature must continue long enough to make sure that the whole mass has been penetrated, and not a single bacterium has escaped destruction. Decay is not removed by cooking alone; experience teaches that cooked flesh, eggs, milk, etc., take a much longer time, but finally decay as well as well as raw. If one kills the bacteria already in the flask by means of heat, he must take care that 710 new geians enter fi'om the aii*. For this pui’pose the Italian Abbot Spalanzani, an observer of nature i]i the last centuiy, celebi-ated for his shrewd expeilrnents, melted the neck of the little flask together during the cooking; the result was that the animal and plant material enclosed in the flask remained for all time unchaTiged, without puti'efaction. The French Coiyit Appert used this method in the commence- ment of our, century, in order to pi’otect meat, vegetables, and other foods, by enclosing them in a metal box furnished with a small opening, then cooked them in a watej’-bath a couple of hours, and during the cooking soldei’ed the opening; evei’y housewife knows that food will keep for yeai's ii7 metal boxes without spoiling. Cei’tain industries employ this method in preser\dng food in quantities ; we indeed receive beef fi'om Austi’alia, and mutton from America, which is perhaps years old, but which when used is as if fi-esh. The assertion has been made that the materials enclosed in the glass flask of Spalanzani, and the metal box of Appei’t, remained fresh not because there were no bacteria iii them, but rather be-
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