140 
IO or 12 organisms that fulfil all these necessary conditions ; 
if motility and indol are left out, there are more than 20 
bacilli, to be regarded as equally objectionable in a water 
sample. 
To take Houston’s definition of true coli first: of the 
239 samples, which have been worked through in our labor- 
atory, derived from 18 different water-supplies, in 3 separate 
quarters of 1909, only 84 would show no “‘ coli.’’ If Savage’s 
wider statement be accepted, it means that we have practi- 
cally not a single supply in the Madras Presidency that does 
not show objectionable fecal contamination. Is it reason- 
able to urge that we in India should have condemned all these 
different water-supplies ? 
There is another point that demands notice. Take the 
organism bacillus cloace as an example ; it will be observed 
that this organism does not come within Houston’s definition 
of ‘* true coli,’’ because it ferments saccharose ; nor within 
Savage’s group that indicates fecal contamination, because 
it liquefies gelatiné, yet it is undoubtedly fecal in origin. 
Why should the mere fact that this organism liquefies gelatine 
mean that it does not indicate facal contamination to an 
equal extent as any non-liquefier? Surely, considering it 
originally came from the feces of man or some other animal, 
the coincidence that it liquefies gelatine cannot put it beyond 
the range of indicators of faecal contamination. As a matter 
of fact, B. cloace, when found by itself in samples, does not 
indicate recent and dangerous pollution; it is, as we have seen, 
a resistant organism, with a fondness for the bottom of lakes, 
and river sand ; but the liquefaction of gelatine has nothing 
to do with these facts. 
The weak point of the above method lies in the statement 
that a large number of what we believe to be entirely different 
species of bacilli equally represent dangerous faecal contanun- 
ation. If this be so, it should be demonstrable that these 
different species are equally resistant to such forces of nature 
as the action of sunlight and the action of storage. Otherwise 
if it can be proved that one organism is particularly resistant, 
and another particularly susceptible to these natural forces, 
it is obvious that the resistant organisms cannot be consid- 
