274 



C.-E. A. WiNSLOW AND E. E. LOCHRIDGE 



TABLE 6. 

 Action of Acetic Acid on B. coli in Tap Water. 



TABLE 7. 

 Action of Benzoic Acid on B. coli in Tap Water. 



TABLE 8. 

 Action of Benzoic Acid on B. typhi in Tap Water. 



_ Add Parts 

 in 1,000,000 



Hydrogen 

 Parts in 

 1,000,000 



Normality 



Per Cent of 

 Dissociation 



Dissociated 



Hydrogen. 



Parts in 



1,000,000 



Bacteria per 

 c.c. before 

 Treatment 



Percentage Re- 

 duction of Bac- 

 teria after 40 

 Min. 



29.23 

 140.30 

 243 . 80 

 333.00 

 42 7 . 00 

 689 . 00 

 1,292.00 



.24 

 15 



.00 

 73 



■52 

 75 

 10.60 



0.0002 

 0.0011 

 0.0020 

 o . 002 7 

 0.0035 

 0.0057 

 0.0106 



40.0 

 20.3 

 15-4 

 13-6 

 10.4 

 9.8 



7-2 



10 



23 

 31 

 37 

 37 

 56 

 76 



50,000 



44.00 

 54.00 

 62.00 

 70.00 

 92 .00 

 100.00 

 100.00 



the 100 per cent reduction at 0.0935 normal. The acid at these 

 strengths is only a little over i per cent dissociated, and the amount 

 of dissociated hydrogen present a little over 1.2 parts per million. 

 Since this is only about one-sixth the strength of ionic hydrogen 

 necessary to produce similar results with the mineral acids, it is evi- 

 dent that the toxic action of the acetic acids is due chiefly to the anion 

 or the undissociated molecule, the latter, being so much greater in 



