157 



tions of them of such concentration that they contained .05 grams of 

 salt per cc. of solution. One cc. aliquots of the proper solutions were 

 added to aliquots of the media using a 1 cc. pipette graduated to .01 cc. 

 This was to give a concentration of the salt of 1.0 gram per liter of 

 media. 



The flasks were tightly plugged with cotton and autoclaved for 

 different lengths of time under 17 pounds pressure of live steam. It 

 was assumed from previous tests that the one cc. of water added with 

 the salt would be lost in the autoclaving. As soon as autoclaved ap- 

 proximately 100 cc. of boiling carbon dioxide free distilled water was 

 added to each flask. Titrations were made at the temperatures specified 

 using 2 drops of 0.5 per cent solution of phenolphthalein as indicator 

 and N/10 carbonate free sodium hydroxide. The results are given in 

 Table III. 



TABLE III. 



Acidity of Ag.\r Ag.vr .\nd Ag.\r Plu.s Gel.\tin'e Medl\ ,\s Affected by Salt-s .\nd Length of time 



OF Sterilization. 



(Figures express cc. normal alkali needed to neutralize 100 cc.) 



