Sessional_Paper_1911 — Page 229

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With older filters there has been a higher bacterial count. On one or two occasions the old water supply was found to contain Bacillus Coli Communis but in no instance has this organism been obtained from the new water supply.

Water is condemned for drinking purposes in which B. Coli Communis is found or when the water contains about 500 nicro-organism per c.c.

SINGAPORE.

A very valuable investigation of the Singapore Water Supply, both as regards its Bacterial contents and as to the efficiency of the filtration, was carried out by Dr. G. A. Finlayson, the Bacteriologist, and the results are contained in the Administration Report of the Singapore Municipality 1905.

The rate of filtration recommended is that of 400 gallons per sq. yard per day giving a Bacterial content of a little over 40 organism per c.c. in the filtered water.

On the important question of the presence of the B. Coli Group, Dr. Finlayson expresses the following opinion (p. 74):

"Suffice it to say that B. Coli or organisms so strongly resembling B. Coli that they may well be included in the large and expanding Coli Group can be readily isolated by means of MacConkey's medium from 5 to 1 c.c. of water.'

The opinion is also expressed that the water "cannot be regarded as otherwise than wholesome and fit for drinking purposes

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As these findings naturally carried much weight, it is necessary to consider, as has been pointed out above, on what grounds the organisms were included in the Coli Group.

In Appendix C p. 94 of the Report, a table is given grouping together these organisms under the title "Coli form Organisms". The tests used were as follows:-

Morphology, Motility, Gram's stain, Bouilion, Agar Streak, Gelatine Streak, Milk, Litmus Bouilion, Glucose Agar, Neutral Red Agar, Peptone water and l'otate. There are 8 Types of "Coli form organisms" described, of which the following is a brief summary:

5 out of the 8 liquefied gelatine within 10 days, 3 of the five are described as doing so rapidly. 2 of the five gave no change in milk and I gave clot with subse- quent liquefaction of the casein. The other 2 gave no gas on glucose agar.

3 did not liquefy gelatine in 10 days; of these :-

1 gave no change in milk, no gas on glucose agar, no fluoresence on Neutral

Red and no Indol on Peptone water.

1 gave no gas on glucose agar and no fluoresence on Neutral Red.

1 B. Coli gave positive reactions to the tests.

As has been pointed out above, opinions vary very much as to what organisms can be called members of the Coli Group. But there is now a very general agreement on the essentialness of certain characters whatever other characters may be absent.

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It seems to me to be impossible to admit into the Coli Group organisms which liquefy gelatine within 10 days, or which do not ferment Lactose and Glucose with Acid and gas production. On this standard, 7 out of 8 of the above "Coli form Organisms would be at once excluded as not members of the Coli Group. Similar organisms have been repeatedly isolated in the investigation of the Pokfulum Water but have been discarded as of no relative importance as soon as their true nature became evident.

* The water here means the unfiltered water (note from Dr. Finlayson, 15th May, 1911).