DISINFECTION STUDIES 



199 



experiments. That is, the decline in bacterial population at 

 each temperature occurred under practically constant concen- 

 tration of atmospheric gases. It is interesting to note, however, 

 that at 0°, 10°, 20° and 30°C. the concentrations of oxygen oc- 

 curred in the ratio of 980:790:049:526. This observation takes 

 on a certain theoretical significance when con.sidered in the 

 light of the findings of Paul, Birstein and Reuss (1910) that 

 dried staphylococci die off at a rate approximately proportional 

 to the square root of the oxygen concentration. The experi- 



TABLE 2 

 The reabsorption of atmospheric oxygen by auloclaved distilled water* 



* The water was autoclaved for ten minutes at 15 pounds, allowed to cool to 

 room temperature and was held in an air thermostat for twelve hours. The 

 water was well shaken before each successive sample was removed for analysis. 



ments of WTiipple and Mayer (1900) in this connection are 

 interesting. They found that exclusion of oxygen from water 

 containing colon and typhoid bacteria resulted in a rapid de- 

 crease in the bacterial population. The contradiction between 

 these observers may perhaps be more apparent than real. 



Jacobs (1920) has sho^vTl for tadpoles that CO2 may produce 

 a lethal effect which is accounted for by a specific penetrability. 

 Koser and Skinner (1921) studying the viability of the colon- 

 typhoid organisms found that carbonation of water causes a 

 rapid diminution in numbers. Our experiments throw no Ught 

 upon this phase of the problem. Carbon dioxide was present 

 in our solutions in presumably constant, small amounts; and its 

 effect should be present to the same degree in all experiments. 



