238 



Stephen DeM, Gage 



ordinary water bacteria by coagulation and sedimentation, and by 

 filtration, is greater than is the removal of bacteria capable of devel- 

 oping at 40°, as previously noted in the discussion of the 30° series. 

 The peculiar significance in the ratios between the bacteria and the 

 acid-formers at 20° appears to be in the much larger ratios obtained 

 for sewages and the effluents from sewage filters than for the other 

 waters examined. This distinction does not hold true for the 40° 

 and 50° bacteria-acid-producing-organism ratios, the high and low 

 values being distributed among all classes of waters. 



TABLE 5. 



Bacterial Ratios for Different Classes of Waters, 20°, 40°, and 50° C. Series. 



Regular sewage 



Station sewage 



Septic sewage 



Sand Filter No i 



" " "2 



4 



'9 



Trickling Filter No. 135, 



' 136. 



Contact Filter No. 1 75 . . . 

 176.., 



251... 



Canal 



Intake 



Applied 216 



Filter No. 8 



" " 216 



" 243 



City filter 



City water 



Pond No. I 



" " 2 



Driven wells 



Shallow Well No. i 



" " "2 



Spring No. i 



" " 2 



Ratio between 

 Total Bacteria 

 at 20° and 

 Bacteria De- 

 veloping at 



40 



19.00 

 21.50 

 26.00 

 S3. 80 

 II .40 

 10.00 



25.30 



II . 20 



8.70 



17.70 



15.20 



29.30 



0.68 



I. 22 



7.56 



9.40 



23.80 



1. 61 



70 

 80 

 70 



25 

 00 

 20 



14.20 

 0.00 

 2.50 



So°C. 



o 



I 



o 



I 



o 



o. 



o 



o 



o. 



5- 

 2 . 

 o. 

 o. 

 o. 

 o. 



3 

 o. 

 o. 

 o. 



I 56 



0.00 

 00 

 00 

 00 

 00 

 00 

 00 



23 



80 

 08 



22 



00 

 08 

 30 



95 

 23 

 70 

 10 

 IS 

 03 

 02 



07 

 12 

 28 

 00 

 67 



Ratio between 

 Total Bacteria 

 at 20° and 

 Number of 

 Acid - Produc- 

 ing Bacteria at 



40° C. 



II .60 



16.90 



18.50 



72,80 



5 -70 



9. 20 



23.00 



8.80 



510 



15 50 



II .50 



IS 00 



0-53 



0.79 



2.36 



312 



14. 10 



0.00 



"•35 



4.70 



3 70 



7.40 



0.00 



o. 10 



10.80 



0.00 



2.50 



50 



015 



1.49 



COS 



0.61 



0,00 



0.00 



0.00 



0.65 



0.09 



so 



10 



07 



01 



01 



04 



12 



14 



00 



67 



1.56 

 0.00 

 00 

 00 

 00 

 00 

 00 

 00 



Ratio between Number 01 

 Bacteria at each Tem- 

 perature and Acid-Pro- 

 ducing Bacteria at That 

 Temperature 



20° C. 



48 

 62 



so 



83 

 27 



98 

 69 

 76 



75 

 63 

 41 

 15 

 59 

 19 

 36 

 26 

 9 

 17 

 30 

 42 

 00 

 00 

 16 



12 

 10 



40 



62 



79 

 71 

 87 

 SO 

 92 

 91 

 78 

 S8 

 87 

 76 

 51 

 78 

 65 

 31 

 33 

 59 

 00 

 77 

 60 

 100 



63 

 00 

 50 

 76 

 00 

 100 



SO 



57 

 84 

 59 

 50 

 00 

 00 

 00 

 65 

 37 

 96 



100 

 41 

 40 

 SO 

 50 



100 

 SO 

 00 



100 



100 

 00 

 00 

 00 

 00 

 00 

 00 

 00 



Bacterial determinations at 20° and 40° on polluted waters. — In 

 addition to the results obtained in the 30° and 50° series previously 

 discussed, we have somewhat more extended information regarding 

 the relation between the numbers of bacteria developing at 20° and 

 at 40° C. Throughout 1905 both total colonies and red colonies 

 were counted on all litmus-lactose agar plates. Comparative counts 

 are thus available on some 200 samples of sea waters, and on samples 



