198 



BAENETT COHEN 



It is evident from mere inspection of figures 1 to 4 that effects 

 of temperature, whatever they may have been, were completely 

 screened. 



The air-saturation of the suspension fluids 



Several considerations made it seem desirable to learn to 

 what extent our water samples were saturated with air gases. 

 The method of analysis used makes no claim to absolute accuracy, 

 but gives a good idea of the actual condition present. Table 1 

 shows that distilled water, seven days old, was fully aerated 

 at each temperature. To determine how soon saturation would 



TABLE 1 

 Dissolved oxygen and carbon dioxide in distilled water held at different temperatures 



for seven days 



occur under the conditions of our experiments, the following 

 experiment was carried out. Bottles containing 900 cc. distilled 

 water and an air space of 100 cc. were autoclaved, allowed to 

 cool while closely stoppered and then held at 0°, 10°, 20° and 

 30°C. respectively for twelve hours. The bottles were then 

 thoroughly shaken, and samples removed for gas analysis as 

 indicated in table 2. The results show that within four to six 

 hours the waters were practically saturated with air. (COj 

 determinations are not given because the minute quantities 

 present were within the limits of error of the method employed.) 

 These observations confirm occasional tests which showed 

 that our bacteria were exposed to an air-saturated en\'ironment. 

 As a consequence we may assume that the gas tensions were 

 practically invariant at each temperature throughout these 



