54 



BACTERIA 



RIVER THAMES WATER COLLECTED AT HAMPTON 



Number of Micro-organisms Obtained from i cc. of Water. 



Again, another example : 



RIVER LEA WATER COLLECTED AT CHINGFORD 



Number of Micro-organisms Obtained from i cc. of Water, 



" During the summer months these waters are purest as 

 regards micro-organisms, this being due to the fact that 

 during dry weather these rivers are mainly composed of 

 spring water, whilst at other seasons they receive the wash- 

 ings of much cultivated land." Frankland. 



