f//^ 



342 



THE BEGINNINGS OF LIFE. 



organisms 



He came to the conclusion that if fluids with an 

 alkaline reaction were raised to the temperature of 

 boiling water^ the organisms contained in them were 

 not all destroyed, because such fluids were subsequently 

 found by him to yield living things when experimented 

 with in the manner adopted by Schwann- and simi- 

 larly he believed that the organisms in these fluids 

 were destroyed when the fluids had been raised for 

 however short a time to a temperature of iio^C 

 (230'' F), because after such treatment no 

 were to be met with in the flasks to which calcined 

 air alone had been admitted. 



The conclusions drawn by M. Pasteur from his re- 

 searches on the subject at present under discussion, may 

 be summed up thus : — (i) When acid solutions of organic 

 matter are employed, no living things are to be met with 

 in repeating Schwann^s experiments, because all pre- 

 existing organisms are destroyed, and living things are 

 believed to be incapable of arising de novo^ but (2) when 

 neutral or slightly alkaline solutions are made use of, 

 organisms may be met with if such infusions are merely 

 raised to the temperature of 100° C, though (3) they are 

 never to be seen when similar infusions have been raised 

 to a temperature of iio°C. On account of these sup- 

 posed facts, and on the strength of a chain of indirect 

 evidence, M. Pasteur assumes, that whilst Bacteria are 

 destroyed in acid fluids at a temperature of 100^ C, their 

 hypothetical ^ germs ^ are not destroyed in a neutral or 

 slightly alkaline fluid at 100^ C, though they do cease 



taof existing^ 



i 



2\ 



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