CHAPTER III. 



QUANTITATIVE ANALYSIS continued. 



THE MULTIPLICATION OF MICRO-ORGANISMS 

 IN WATER. 



MIQUEL'S researches showed that in surface waters, such as rivers 

 containing a large number of micro-organisms, the multiplication 

 is slow and persistent, whilst in deep well waters and springs, 

 containing only a few bacteria, the multiplication is rapid but 

 soon followed by a marked and steady decrease. 



Frankland's experiments with the rivers Thames and Lea gave 

 the following results : 



Day after collection. After 2 days in the After 4 days in the 



dark at 20 C. dark at 20 C. 



Organisms per c.c. Organisms per c.c. Organisms per c.c. 



Kiver Thames) 

 .t Hampton/ 12 ' 25 *' 386 2 ' 18 



R j rl f? t } ... 7,300 2.H8 1.286 



Chmgford 



The number of micro-organisms in the river water underwent 

 a marked diminution after storage for from two to four days in 

 stoppered bottles. 



An examination of a deep well water gave results analogous to 

 those obtained by Miquel. 



Day after collection. After 3 days in the After 16 days in the 



dark at 20 C. dark at 20 C. 



Bacteria per c.c. Bacteria per c c. Bacteria per c.c. 



Kent Well ... 96 ... 178,379 ... 51,843 



Cramer's experiments on filtered water from Lake Zurich also 

 strongly supported MiquePs observations as to the changes 

 occurring in pure waters. He filled a sterilised flask with the 



