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 : 



Number of colonies obtained from 1 c.c. 



Description 



Kent Well 



Day after 

 collection 



96 



Standing 3 days 

 at 20 C. (dark) 



178,379 



Standing 16 days 

 at 20 C. (dark) 



51,843 



In considering these results, it must be remembered 

 that at the outset this water is almost wholly free from 



