GROWTH OF MASSIVE CULTURES OF BACTERIA 31 



remove with anything like completeness the bacterial 

 growth from one hundred Roux flasks were greater than 

 we could afford to exert more than a few times; therefore, 

 attempts to secure the desired quantity of bacterial cellular 

 substance by this method were abandoned. We then tried 



FIG. 3 



The incubating room, lids lowered. 



growing the colon bacillus in ordinary moist chambers, used 

 as Petri dishes, but with the greatest care many of these 

 cultures became contaminated. Finally, we devised the 

 large copper double tanks which have proved wholly satis- 

 factory and have supplied abundant growths, easily obtain- 



