322 APPENDIX. 



ing organic liquids : — urine in its natural conditions ; in- 

 fusions 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 complete. 



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. 



Infusions of the substances above referred to were 

 afterwards exposed in succession to air which had been 

 freed of its floating matter by filtration through cotton 

 wool, also to air from which the floating matter had been 

 removed by calcination, and finally to vacua obtained by 

 exhausting as far as possible with an air-pump, large 

 receivers which had been previously filled with filtered air. 



Boiled for five minutes and exposed to air thus treated, 

 or to vacua thus produced, none of the infusions showed sub- 

 sequently any alteration of colour or of transparency to the 

 naked eye, or to the microscope any manifestation of life. 



Thus far are summed up the results obtained with 

 self-purified air, filtered air, calcined air, and air-pump 

 vacua, the liquids in all cases being exposed in open test- 

 tubes. Small retort-flasks, with drawn-out necks, were 

 afterwards resorted to. Charged with the infusions, they 

 were boiled in heated oil or brine, and sealed with ex- 

 ceeding care during ebullition. At the Royal Society on 

 January 13, 1876, one hundred and thirty such flasks 

 were submitted to the Fellows, free alike from putrefaction 



