DISTRIBUTION OF B. COLI COMMUNE 
129 
TABLE V (b) 
Experiment II 
No. 
No. of hours' 
exposure to 
current of dry 
air 
Appearance on plate (piece of 
paper incubated for 24 hours 
with 10 c.c. broth and I c.c. 
plated). 
October 4, 10-4.C a.m. 
O 
00 Colonies 
2 
„ ,, 1 2 noon 
>* 
CO ,, 
3 
„ „ 2-30 p.m. 
+ 
CO 
+ 
+-3° P- m - 
6 
00 „ 
5 
„ 8-45 p.m. 
10 
co 
6 
„ 5, 10-35 a - m - 
24 
Sterile 
APPENDIX— TABLE VI 
This table shows the efficiency of sand filtration for removing B. coli 
commune from water ( see this vol., pp. 1 5 and 1 6). The samples were taken 
from a sand filter bed while it was being cleaned. The bed was used to filter the 
Rivington supply of the Liverpool drinking water. 
Date 
No. 
Description of Sample 
B. coli per gram 
Remarks 
Sample taken July 2, 1900, 
analysed July 3, 1900 
1 
Sand from unscraped surface 
of filter bed 
20 
Sand appeared very 
dirty 
Sample taken July 2, 1900, 
analysed July 3, 1900 
2 
Sand from same bed, after the 
surface (about \ inch deep) 
had been scraped off 
Absent in -3 grm. 
Sample taken July 2, 1900, 
analysed July 3, 1900 
3 
Sand, similar to No. 1, after 
washing 
