68
SAMPLE V.—WESTERNMOST TAP NEAR RAILWAY STATION COM-
POUND.
N u m b e r .
L a c t o s e .
S a c c h a r o s e .
D u l c i t e . Ad o n i t e .
I n u l i n .
V o g e s a n d P r o s k .
I ndol .
Mo t i l i t y .
G r o u p .
Name of Bacilli.
Group and
Remarks.
Total colonies per cc. on agar at 37°—80.
Bile salt lactose medium.
+
—
1 tube of 20 co.
..
..
..
..
1
1 + + + + — — — — III B. Pneumoniæ .. Group I, nil.
2 tubes of 10 cc.
..
..
..
..
1
1
2 + + — — — — + — IV B. Coscoroba
..
„ II, nil.
3
„
5 cc.
•.
..
..
..
..
3
3 + + —— — — — — III B. Pneumoniæ ..
„ Ill, 9.
3 „
1 cc.
..
..
..
••
..
3
4 + + + + ———— III
Do.
..
„
IV, 1.
3
„
.1 cc.
..
..
..
..
..
3
5 + + + — — — + — III B. Neapolitanus.
3
„
.01 cc.
..
..
..
..
..
3
6 + + + — — — + —III
Do.
7 + + + — — — + — III
Do. ..
Class I, nil.
Fœcal bacilli present in 60 cc. and upwards.
8 + + + ———+ — III
Do.
.. ,, II, 10.
9 + + + + — — — — III B Pneumoniæ .. „ III, nil.
No vibrios in 100 cc.
10 + + — — ——+
III B. Neapolitanus.
REPORT.
Quantitatively the water of the storage tank can only be described as grossly polluted, although the
evidence goes to show that this is not of recent occurrence. From this water containing nothing but the
most resistant forms, the change to the next sample is almost startling. The great majority of the germs
have been apparently removed, but an entirely new flora, and that of a kind which in the present state of
our knowledge we must associate with recent and dangerous pollution has been substituted. What c ir
c u m -
stances may have given rise to the fouling of the post filtration passages with the highly susceptible
organisms of Class I remain obscure. It is notable that Oxytoccus perniciosus also made a sudden appear-
ance at this time in the Cocanada water-supply, so that the cause is not necessarily strictly local. These
organisms being found in the filtered water gives rise however to rather disquieting ideas. The next
sample from the easternmost tap near the Beach is very much better. A very small total count, notable on
this account, fœcal germs in 10 cc. and upwards and these represented by only a few very resistant
kinds, this water may be said to be in a very good condition. The water from the southernmost tap is
very much worse and seems to have picked up a large number of germs from the pipes, most of which
are excremental in origin. This pipe line would probably be much the better of being scoured out. Sample
V from the westernmost tap near the railway station compound is again remarkably pure, so that this set of
samples may be said to have formed a record in fluctuations. Chemically the water is quite good.
Chemical Analyses.
SAMPLE I.
SAMPLE V.
Physical appearances.
Colour and
Transparency.
White and opaque.
White and hazy.
Smell.
None.
None.
QUANTITATIVE.
Total solids
..
..
.. Parts per 100,000
15.000
15.000
Temporary hardness..
•
Do.
5.000
4.500
Permanent hardness
....
Do.
• •
1.500
2.500
..
Total hardness..
Do.
6.500
7.000
Chlorine
..
..
..
Do.
1.420
1.420
Ammoniacal nitrogen ..
..
Do. . .
0.002
Trace.
Albuminoid nitrogen ..
..
Do.
0.004
0.003
Oxygen absorbed (Tidy's Process)..
Do.
0.047
0.015
Nitric nitrogen
..
... •
Do.
• •
Trace.
0.025
QUALITATIVE.
Nitrites
..
..
..
• •
..
• .
Nil.
Nil.
Sulphates
....
..
Present.
Present.
Phosphates ..
• •
• •
• •
..
..
Nil.
Nil.
Iron, poisonous metals ..• .
..
Nil.
Nil.