QUANTITATIVE BACTERIOLOGICAL ANALYSIS. 29 



Karlinski studied a lake in Herzegovinia and found near the shore 

 16,000 bacteria per c.c. At the centre of the lake, however, 

 3000 organisms per c.c. were found at the surface ; at a depth 

 of five metres 1000 ; at ten metres 600 ; and at fifteen metres 

 only about 200 a3robic organisms were detected. 



Wells. Great differences have been found in the number of 

 bacteria present in shallow wells. Egger examined a large 

 number of wells in Mainz with the following results : 



Maschek obtained the following results in Leitmeritz : 



B. Fischer's examinations in Kiel gave the following counts : 



51 wells 

 34 , 



Up to 500 

 500-1,000 



64 wells 

 22 , 



1,000-10,000 

 10,000-20,000 



Deep wells as a rule contain few bacteria. Frankland found 

 in a Kent well, sunk in the chalk, between 6 and 26 organisms 

 per c.c. ; and in his report to the Local Government Board on 

 the monthly bacteriological examination of the London Water 

 Supply for the years 1886, 1887, 1888, he gave the results 

 shown in the following table : 



Number of bacteria per c.c. 



Wells. 



Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. 



1886. 



New wells , 



II 



12 



3 



59 27 30 



9 



DO 



3 



5 

 65 



4 



18 

 19 



11 



6 

 12 

 67 



34 



