Il6 BACTERIOLOGICAL METHODS 



ing the larvae of Nematodes and the spores of fungi, to say nothi 

 of dead and decayed animals as mice, rats, rabbits, frogs, etc. 



In many instances the contamination (by bacteria and algae) 

 the water supplies of cities and towns is so extensive as to make di- 

 rect counting easy. We hereby give the report of the microscopical 

 examination of a sample of water from a Berkely (California) 

 reservoir, analyzed in March, 1912. 





Diatoms 1,500,000 per cc. 



Desmids 860,000 per cc. 



Oscillaria filaments 125,000 per cc. 



Bacteria 16,500,000 per cc. 



Paramecia. 60,000 per cc. 



Spores 5,oco per cc. 



Hyphae of fungi 460 per cc. 



The water was at the time decidedly greenish in tint with a dis- 

 agreeable odor, due to the numerous algae present. Water show- 

 ing such a high and varied biological count shows surtace seepage 

 and indicates sewage contamination and is not fit for drinking 

 purposes, yet the biologist for the water company declared it good 

 and harmless. The only interpretation that can be put upon a 

 count such as the above is that the water supply is dangerously 

 contaminated. Diatoms and desmids feed upon dead and decay- 

 ing vegetable matter. Oscillarias occur in wet soils rich in humus. 

 Paramecia feed upon decaying organic matter. The molds like- 

 wise are proof of the decay of organic matter, animal and vegetable. 

 In all cases of evidence of surface seepage, sewage contamina- 

 tion may be suspected and all sewage contaminated drinking 

 waters are a menace to the public health. 



In no case should the examination of concentrated (1000 cc. 

 reduced to 10 cc.) and centrifugalized sediment be omitted, as this 

 will perhaps reveal contaminations which might be overlooked in 

 the direct examination. Nor must the presumptive colon bacillus 

 test be omitted when there is the least indication that sewage con- 

 tamination exists. In case of slight but suspicious contaminations 



