yee < e 
ao ie 

103 
cially polluted tanks (even though a laboratory culture is 
used) the same results were obtained. The organism is 
always associated with recent pollution. This has been 
shown by the use of the glucose and lactose broth. We 
have never found that true coli communis are present when 
the acid and gas line in the two media is widely separate. 
On one occasion we did find that this organism was present 
in the water of a lake which we knew was low and had been 
exposed to the sun for a period of 7 months without rain ; 
but on inspecting the locality it was discovered that the 
catchment area had been largely contaminated by cattle 
(as it was the only available grazing in the district), and 
that buffaloes had been wallowing at the edge of the lake. 


TABLE X (a). 
Percentage number of typical B. coli, which did not ferment 
Saccharose. 
| Raw Thames Raw Lee Raw New | New River 
1908-9. Thames filtered ieee filtered River filtered 
Month. water. water. water. water. water. water. 
232 4,951 232 409 232 1,353 
samples, | samples. | samples. | samples. | samples. | samples. 
Coals ie 2 ae 4. ie 6. 
1908. 
April 85°7 86:2 85°3 I out of I 71°4 4 out of 5 
May 65°6 70°0 74°0 1) es ae 7:5 a? 3. 
June 772 59°7 60°7 43°7 62°7 ware e 
July 53°3 54°2 63°5 54°5 63°1 50°0 
August 460°4 50°8 62°1 2 out of 2 59°1 36°4 
September VB ge | 57°9 7 be pe OJ? bg 66°0 3 out of 9 
October 70°8 57°0 78°2 4 8 74°6 53°8 
November 70°! 70°2 84°7 Dt ere gs 72°9 75°0 
December 80°6 81°5 88°5 83°3 70°7 Srl 
1909. 
January .. go"4 84°0 83°3 6 out of 7 67°8 80°9 
February. . yo"4 86°8 84°5 ae Pa | 73°9 2 out of 3 
March 93°5 82°& 88°0 81°8 79°5 66'7 
Average 74°4 SEO mae 63°6 69°6 67°0 
(727 (1,029 (813 (77 (520 (176 
| specimens)! specimens)! specimens) specimens)! specimens) | specimens) 
Some of the figures in columns 4 and 6 are too few in number to be dealt with by 
this percentage method. 
