52 ORIGIN OF LOWEST ORGANISMS. 



a fluid which is eminently suitable for testing the vital 

 resistance of Bacteria, one which, although quite 

 capable of nourishing and favouring their reproduc- 

 tion, does not appear capable of evolving them, when, 

 after previous ebullition, it is enclosed in a her- 

 metically sealed flask from which all air has been 

 expelled. Three flasks were half-filled with this solu- 

 tion.* The neck of the first (a) was allowed to remain 

 open, and no addition was made to the fluid. To the 

 second (b), after it had been boiled and had become 

 cool, was added half a minim of a similar saline solu- 

 tion, which had been previously exposed to the air, 

 and which was quite turbid with Bacteria, Vibriones 

 and Torulce. From this flask after its inoculation 

 with the living organisms the air was exhausted 

 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 90 F. The third flask (c) was 

 similarly inoculated with living Bacteria, although its 

 contents were boiled for ten minutes (at 2I2F.), 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 



* In the proportion often grains of neutral ammonic tartrate, 

 with three grains of neutral sodic phosphate, to an ounce of dis- 

 tilled water. 



