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Ty/fi' BEGINNINGS OF LIFE. 



327 



though its 



by means of an air-pump, and its neck was hermeti- 

 cally sealed during the ebullition of the fluid, without 

 the flask and its contents having been exposed to 

 a heat of more than 9o°F. The third flask [c] was 

 similarly inoculated with living Bacteria^ 

 contents were boiled for ten minutes (at 3i3°F), and 

 its neck was hermetically sealed during ebullition. The 

 results were as follows : — the solution in the first flask 

 {a\ became turbid in four or five days; the solution 

 in the second {b), became turbid after thirty-six hours ; 

 whilst that in the third flask (c), remained perfectly 

 clear. This latter flask was opened on the twelfth 

 day, whilst its contents were still clear, and on micro- 

 scopical examination of the fluid no living Bacteria 

 were to be found. This particular experiment was 

 repeated three times, with similarly negative results, 

 although on two occasions the fluid was only boiled 

 for one instead often minutes. 



It seemed, moreover, that by having recourse to 

 experiments of the same kind, the exact degree of heat 

 which is fatal to Bacteria and Torul^ might be ascer- 

 tained. I accordingly endeavoured to determine this 

 point. Portions of the same saline solution, after having 

 been boiled ^ and then cooled, were similarly inoculated 



r 



J 



^ It was necessary to boil the solution first, in order to destroy any 

 living things or dead ferments which it might contain. As before 

 stated, it must contain one or the other of these, because an unboiled 

 solution of this kind, in a corked bottle about half full, will always 

 become turbid ; whilst, after it has been boiled, it may be kept inde- 

 finitely under similar conditions without becoming turbid. 



