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144
contamination, whether from sewers or cesspools, from sewage works,
or the drainage from manured land. These animal substances may
all of them be at any time accompanied by morbific matter, capable
of producing zymotic disease, and the subsequent treatment of the
water, although it greatly diminishes the risk, does not ensure the
entire removal of such matters, should they be present."
"The improvement effected in the river water by filtration, revealed by the
determinations of the relative numbers of micro-organic spores or
germs present in a given volume of the raw and filtered waters, is very
striking. These determinations have been made by Dr. Percy Frankland
during the past year, and the results show that whilst the
unfiltered Thames water exhibited, by gelatine cultivation, on an
average, 2,219 germs per cubic centimetre, the filtered water contained
only 38, which corresponds to a reduction of 98.3 per cent."
When examined under the microscope, the sediment deposited by turbid
water, on standing, is generally found to contain living and movingorganisms.
The occurrence of such organisms has become increasingly
rare in late years, and last year was not observed on any occasion, the
several waters being examined monthly.

The Water Examiner's Report.—I turn now to the Annual
Report of Colonel Sir Francis Bolton, R.E., which contains
information of much general interest. The duties of this