Table 1. — Bacterial counts, at irregular intervals, of unialgal G. brevis culture, 

 companion G. brevis- free culture, and replenishment medium from common 

 reservoir 



Bottle No, 



Incubation 

 period 

 ( days ) 



No. bacteria 



per ml 



(millions) 



Remarks 



(Unialgal G. brevis ) 



2 

 (G. brevis-free bacteria) 



3 

 (Reservoir, uninoculated) 



Shortly before 

 inoculation 



0.000070 

 0.000090 



Media cooled to room 

 temperature after final 

 heating before collecting 

 sample ; plates prepared 

 shortly thereafter. 



1 

 2 



Shortly after 

 inoculation 



0.014 

 0.018 



Plates prepared shortly 

 after collecting 

 samples . 



1 

 2 

 3 



0.37 

 0.41 

 0.0015 



Samples refrigerated 

 5 days before preparing 

 plates . 



1 

 2 



2.7 

 1.8 

 0.26 



Samples refrigerated 

 2 days before preparing 

 plates. 



1 

 2 

 3 



14 



2.0 

 1.8 

 0.13 



Plates prepared 15 to 

 20 minutes after 

 collecting samples. 



y 



,1/ 



25 



1.4 



1.2 



12.2 



Samples refrigerated 

 2 days before preparing 

 plates. 



1/ The value of 12 million bacteria per ml for the reservoir appears to be exces- 

 sively high when compared with the other counts obtained at either earlier or 

 later intervals. With the exception of the presently considered value, the 

 highest bacterial count obtained from the reservoir was 1.8 million per ml 

 (Table 5, Experiment 7). 



