THE MULTIPLICATION OF MICRO-ORGANISMS 223 



Thus the multiplication in these waters is very 

 marked, even when preserved at the low temperature of 

 a refrigerator, and clearly indicate the inadmissibility 

 of delaying the bacteriological examination of a sample 

 of water beyond a few hours, even if the sample be 

 packed in ice. 



An examination was then made of the deep-well 

 water obtained from the chalk, which, as is well known, 

 contains but the merest trace of organic matter, and 

 presents, therefore, in this respect a marked contrast to 

 the river- waters described above. The following re- 

 sults show that the power of multiplication possessed 

 by the bacteria in this well-water is altogether enor- 

 mous, thus : — 



Description 



Kent Well 



Number of colonies obtained from 1 c.c. 



Day after 



collection 



Standing 3 days 

 at 20° C. (dark) 



96 



178,379 



Standing 16 days 

 at 20° 0. (dark) 



51,843 



; In considering these results, it must be remembered 

 that at the outset this water is almost wholly free from 



