228 Prof. J. Tyndall on the Deportment of [May 17, 



III. " Further Researches on the Deportment and Vital Resistance 

 of Putrefactive and Infective Organisms, from a Physical point 

 of view." By John Tyndall, LL.D., F.R.S., Professor of 

 Natural Philosophy in the Royal Institution. 



(Abstract.) 



For reasons which will appear in the sequel, it will be desirable to 

 glance, in the first place, at the results already submitted to the Royal 

 Society. 



Portions of the autumn of 1875, and of the winter and spring of 

 1875-76, were devoted to the first section of these researches, and on the 

 13th of January, 1876, its main results were communicated orally to the 

 Royal Society. The completed memoir was handed in to the Society 

 on the 6th Of April : it is published in vol. 166 of the ' Philosophical 

 Transactions.' 



Many of the ' closed chambers' employed in the inquiry were submitted 

 on the 13th of January to the inspection of the Fellows. There had 

 been over fifty of them in all, and several of them had been used more 

 than once. The air in these chambers had been permitted to free itself from 

 floating matter by self-subsidence, no artificial means of cleansing it being 

 employed. Sterilized organic liquids and infusions of the most varied 

 kinds freely exposed to air thus spontaneously purified were found, when 

 tested by the microscope, to remain absolutely free from organisms of all 

 kinds, and equally free from the turbidity, scum, and mould which to the 

 naked eye are the infallible signs of the generation and multiplication of 

 such organisms. 



These experiments embraced, among others, the following organic 

 liquids : — urine in its natural condition ; infusions of mutton, beef, pork, 

 hay, turnip, sole, haddock, codfish, salmon, turbot, mullet, herring, eel, 

 oyster, whiting, liver, kidney, hare, rabbit, barndoor fowl, pheasant, and 

 grouse. 



The number of separate vessels containing these liquids which were 

 exposed to spontaneously purified air amounted to several hundreds, and 

 the consensus of their testimony, in the sense just indicated, was com- 

 plete. 



Five minutes' boiling was found in all cases sufficient to sterilize the 

 infusions. 



When, after remaining sterile for months, the doors of the chambers 

 were opened so as to admit the uncleansed air of the laboratory, the contact 

 of such air, or, more correctly, of the matter mechanically floating in it, 

 infallibly produced organisms in abundance — sometimes exclusively 

 Bacterial, sometimes exclusively fungoid, and sometimes a combination 

 of both. 



