ACTION OF DIBDIN CONTACT BEDS 67 
The Contact Beds 
The effluent from the final contact beds, la and 2a, has always contained a 
considerable amount of matter in suspension, and in large quantity is opaque. The 
effluent also undergoes slight decomposition on standing. The effluent from bed 3<? 
(sand bed) has on the other hand been clear, and has not undergone decomposition on 
standing, or after incubation. In the case of all three effluents, the following figures 
show that the total number of organisms, as well as the numbers of the B. coli, are 
very high. 
Table showing the number of bacteria per c.c, the number of B. coli per c.c, and 
the presence or absence of the B. enteritidis sporogenes in the effluent from bed 2a : — 
No. of 
B. enteritidis 
Date 
Organisms 
per c.c. 
B. coli per c.c. 
sporogenes 
in 0.0 1 c.c. 
November 8th, 180,0, 
270,000 
1,030 
resent 
3,475 
" 
" 10 11th' " 
220000 
21,370 
" 
„ 13th, ,, 
4, 3 2 7,000 
" 
„ 14th, ,, 
24,0/0 
" 
1 ah' 
2 060 OOO 
I 2,770 
" 
1 6th, „ 
2,1 87,000 
7,433 
17th, „ 
1,440,000 
H,570 
1 8th 
1,284,000 
I 3,000 
(in 0. 1 c.c.) 
IOO 
Present 
„ 28th 
667 OOO 
22,500 
" 
• ,196,700 
" 
" 30th' 
1 , 090,000 
'4,3°/ 
" 
December ist 
840,000 
„ 5th, " 
2,460,000 
1 1,000 
7th 
") 8 th', I 
23,000 
»> 9th, „ 
Doubtful if 
13,000 
any 200 (?) 
1 2th, „ 
48,000 
2,700 
„ 13th, „ 
1 3,700 
407 
„ 1 4th, „ 
23,700 
„ 15th, „ 
7,700 
Absent in 1 
Absent 
over 100 c.c. 
1 6th, „ 
12,200 
1 8 th, „ 
3,870 
Present 
„ 19th, „ 
1 57,200 
6,633 
January 8th, 1900 
81,400 
2,000 
Absent 
„ 10th, „ 
360,000 
13,400 
15th, „ 
64,470 
n 19th, „ 
( 1 1 4,000 
1 41,700 
„ zoth, „ 
14,700 
i,333 
23rd, „ 
162,000 
„ 24th, „ 
89,400 
14,000 
Present 
26th, „ 
91,700 
600 
„ 29th, „ 
119,470 
„ 30th, „ 
1 24,800 
