Essays on the floating-matter of the air in relation to putrefaction and infection / by John Tyndall.

  • John Tyndall
Date:
1881
Catalogue details

Licence: Public Domain Mark

Credit: Essays on the floating-matter of the air in relation to putrefaction and infection / by John Tyndall. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    and from life. They embraced specimens of all the sub- stances above mentioned and some others. Briefly expressed, then, the evidence furnished by six months’ assiduous work during the autumn, winter, and spring of 1875-76, proved conclusively that in the atmospheric conditions then existing in the laboratory of the Royal Institution, not one of the many hundred flasks and tubes experimented on failed to be sterilized by five minutes’ boiling, and no countenance was given to the notion that any of these once sterilized infusions possessed the power of spontaneously generating life. The investigation embodied in the memoir now sub- mitted to the Society was opened in the summer of 1876 by a series of tentative experiments on turnip-infusions, to which were added varying quantities of bruised or pounded cheese. Seven different kinds of cheese were employed, fifty-seven test-tubes being charged with the mixture and exposed to the self-purified air of closed chambers. The majority of these mixtures remained unchanged ; a minority became charged with organisms, which are, in my opinion, completely accounted for by reference to the protective action of the cheese. In the memoir of which this is an abstract such protective action is illustrated by the fact that when ordinary mustard seeds were tied together in a calico bag, they resisted the boiling tem- perature for a considerable multiple of the time which sufficed to kill them when no bag enveloped them. The bag and outside seeds protected the interior ones. Not temperature alone, but the ability to diffuse its juices or salts, is a condition of prime importance in the destruction of the integrity and life of a germ by boiling water. Without diffusion a germ may withstand tem- peratures competent to utterly destroy it where diffusion is free. I need not remark on the imperviousness of cheese to water, and its consequent power to prevent diffusion. These summer experiments on turnip-cheese infusions weie, however, merely tentative, and ] purpose completing- them hereafter.