On disinfection by heat : with a description of a new disinfecting chamber / by James Adams, M.D.
- James Maxwell Adams
- Date:
- 1883
Licence: Public Domain Mark
Credit: On disinfection by heat : with a description of a new disinfecting chamber / by James Adams, M.D. Source: Wellcome Collection.
Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.
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![each successive crop as it springs into active life, there was ettectcd ultimately a comjilete destruction. Finally he showed how all preceduig observers had failed in their best intended efforts to procure a condition of the air absolutely or—as he I)hrases it—optically pure; and with this necessary condition ot punty secm-ed, he predicted with an accuracy that has not since been gainsaid, that there never would again occur an example of so-called s])ontaneous generation. The distinction to be observed between the seed itself, and the developing organism, cannot therefore be itoo strongly im- pressed on the mind when dealing with methods of germicide. Notoriously the growing or adult organism can be easily de- stroyed. Not so the seed. The contrasted difficulty has been well expressed by our senior city member, Dr. Cameron, in his very instructive and in every respect excellent monograph on Microbes. Dr. Cameron says as to the spores which they [i.e. the developing or adult organisms] produce, and from which succeeding generations spring, there is almost no killing them. The more you dry them the better they resist destruction. Time is no object with them and they maintain their dormant vitality for an indefinite number of years. Absolute alcohol has no effect on them. As to oxygen they can stand that concen- trated by the pressure of twenty atmospheres, and be none the worse. Two or three hours' boiling if they have been well dried beforehand, seems not to hurt them, and they have even been known to resist eight hours' of the process. The only effective means for their immediate destruction that I am aware of is the Jiame of a spirit lantp. To that their extreme minuteness renders them an easy prey. But Pasteur never saw germs resist 230° F., or the adult organism from 122° to 140° F. when in the moist state. Chaveau, Calvert, Eoberts, Tyndall, and many others, have shown that, from 140° to 212° F. is a degree of heat that few developed germs can sustain. According to the very recent experiments of Koch, Wolffhiigel, Gaffky, and Loefleui', exposure to tempe- ratures of 212° to 221° F. in dry heated air effects easily the destruction of Baccili and adult Bacteria, while spores of mould were not killed after being subjected for one and a half hours to air heated from 230° to 240° F., and spores of Baccili were destroyed only after being confined for three hours in an atmosphere of 284° F. On the other hand, these last-named observers have given very important evidence as to the differ- ence in effect of heat according as it is dry or humid, for they found that spores of garden earth and of carbuncular disease lost all vitality by an- exposui*e of only ten minutes in hot vapour registering 230° F., and they assume that this is the](https://iiif.wellcomecollection.org/image/b21468229_0006.jp2/full/800%2C/0/default.jpg)
