BACTERIAL CONTENTS OF VARIOUS WATERS 107 



wells in Kiel, Breunig ^ found numbers varying between 

 6 and 30 in the c.c. Kowalsky found in some deep- 

 wells in Vienna an average of from 18 to 33. 



All these investigations show what a high degree of 

 bacterial purity is possessed by these deep-wells, and 

 when the enormous depths of porous strata are taken 

 into consideration through which the water gaining access 

 to such wells has to pass, this poverty in microbial life 

 is not to be wondered at. In a subsequent chapter on 

 the purification processes, both artificial and natural, to 

 which water is submitted, this subject will be dealt with 

 in greater detail. 



Spririg-water. — The number of micro-organisms in 

 spring-water, protected from chance contamination, is 

 usually very small, whilst in some cases no organisms 

 at all have been discoverable. Thus Libbertz^ found' 

 no organisms in several samples of spring-water supply- 

 ing Prankfort-on-Main, whilst in other samples collected 

 after heavy rain he only obtained from 50 to 60 in 1 c.c. 



Freimuth^ examined on four different occasions 

 the spring-water supplied to Dantzig, and only once 

 found micro-organisms, and then but two in a c.c. 



Buchner ^ also found no organisms in a spring from 

 Giesing, whilst at another time 5 were obtained. In 

 the Brunnthal spring the same author found from 

 4 to 35 in a c.c. 



In spring-water near Jena, Fllrbringer found from 

 32 to 156 in a c.c. 



A spring in the Upper Greensand near Eeigate was 

 found by one of us to contain 8.^ 



^ Bakteriologische Untersuchung des Trinkwassers der Stadt Kiel 

 im August und SeptemheVf 1887. Kiel, 1888. 



- Arheiten aus dem Kaiserlichen Gesundheitsamt, vol. i. p. 560, 1886, 



2 Ibid, p. 558. 



* Loc. cit. p. 551, 



^ ' New Aspects of Filtration and other Methods of Water Treatment. 

 Percy Frankland, Joitr, Society of Chemical Industry, 1885. 



