70 



ELEMENTS OF WATER BACTERIOLOGY 



AVERAGE NUMBER OF BACTERIA AND ACID-PRODUCERS 

 DEVELOPING AT 20°, 40°, AND 50° C, WITH DIFFER- 

 ENT CLASSES OF WATERS 



Bacteria per c.c. 



20° C. 

 4D. 



40° C. 

 24 Hrs. 



Hrs. 



Acid-producing Bacteria. 



50° C. 

 24 Hrs. 



Sewage . 



Septic eflfluent. . . 

 Contact effluent . 



Trickling filter 

 effluent 



Do 



Canal water .... 



River water ..... 



Settled canal water 



Sand filter effluent 

 (sewage) 



Do 



Do 



Do 



Water filter efflu 

 ent 



Do 



Do 



Do 



Do 



Shallow well .... 



Pond 



Spring 



Driven well .... 



2,990,000 

 1,676,000 

 485,000 

 146,600 

 389,000 

 306,000 



15,500 

 23,300 

 16,400 

 16,900 

 2,800 



1,640 



35 



1,300 



670 



3 



7^5 

 62 



150 



64 



1,000 



507 

 27 



71 

 49 

 80 



41 



557,500 



360,000 



126,500 



26,100 



59,300 



89,600 



1,730 



2,030 



112 



207 



212 



1,375 



4 



130 



170 



3 

 170 



I 

 22 



5 



2 



72 



7,700 

 29,500 



410 

 8,300 

 8,000 



485 



154 



54 



5 



4 



2 



4,400 

 24,900 



240 

 8,000 

 8,000 



200 



100 



20 



2 



2 



I 



In warm weather the interpretation of the body- 

 temperature count must be made less rigid than at 

 other seasons. Recent investigations have shown that 



