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V. Further Researches on the Deportment and Vital Persistence of Putrefactive and 
Infective Organisms from a Physical point of View. By John Tyndall, D.C.L., 
LL.D., F.R.S. 
Received May 14, — Read May 17, 1877. 
§ 1. Introduction. 
On the 18th of January, 1876, I had the honour of submitting to the Royal Society 
some account of an investigation in which the power of atmospheric air to produce life 
in organic infusions and its power to scatter light were shown to go hand in hand. The 
“ scattering ” was proved to be due, not to the air itself, but to foreign matter suspended 
in the air. It was moreover proved that air placed under proper conditions went 
through a process of self-purification, and that, when this purification was visibly 
complete, the power to scatter light and to generate life 
disappeared together. 
The form of the experiments here referred to was, it 
will be remembered, as follows: — Wooden chambers were 
constructed with glass fronts, side windows, and back doors. 
Through the bottoms of the chambers test-tubes passed 
air-tight, their open ends, for about one fifth of the length 
of the tubes, being within the chambers. Provision was 
made for a connexion through sinuous channels between 
the outer and the inner air. The chambers being closely 
sealed, were permitted to remain undisturbed for a few 
days. The floating matter of the internal air gradually 
subsided, until at length an intensely luminous beam 
failed to show its track within the chamber. Then, and 
not till then, were the infusions introduced, by means 
of a pipette passing through the top of the chamber. 
After their introduction, they were boiled in an oil- or 
brine-bath* for five minutes, and afterwards placed per- 
manently in a warm room. 
The annexed woodcut, taken from the ‘ Proceedings ’ of 
the Royal Institution, shows a chamber with its six test- 
* From the fact of their being boiled in oil or brine, Prof. Cohn has inadvertently inferred that the infusions 
themselves -were raised above their boiling-points. The tubes being open, the temperature of ebullition is of 
course independent of the source which provokes it. 
Fig. 1. 
MDCCCLXXVII. 
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