THE PURIFICATION OF WATER, 
173 
sent inquiry, in so far as it relates to the more than possible existence of choleraic germs 
in the water we drink. The agents of those diseases are unquestionably living germs 
capable of remaining dormant for an uncertain but nevertheless not indefinite period, and 
then springing into activity and multiplying themselves without limit directly they find 
the conditions necessary for their active development. But whether these germs are 
susceptible of oxidation, like common dead organic matter passing through its final 
stages of decay, is more than chemical science alone can determine. The analogies in 
physiology are against such a supposition, and they warn us not to receive it even as a 
possible fact. That which we do know, however, is that these germs are destroyed by 
the temperature of boiling water ; that they are killed by all caustic substances, as chlo¬ 
ride of zinc, chloride of iron, etc.; and that they cannot resist the action of certain 
agents, as sulphurous acid and its salts, carbolic acid, which act on them after the 
manner of specific poisons. We must, therefore, look to these agents rather than to 
processes of oxidation for reliable prophylactics; and in the case before us the only agent 
on which we can confidently rely is heat, for if the infected water be boiled the choleraic 
germs will be rendered innocuous. That the destruction of decaying organic matter in 
water is of the greatest importance there can be no doubt, for experience has proved that 
it also is productive of disease. It is, moreover, certain that organic matters of this de¬ 
scription are rapidly oxidized by permanganate of potash, and by filtration through 
animal charcoal, and charcoal mixed with certain compounds of iron, but it is more than 
doubtful, even if it were practicable, whether such processes of purification should be 
used by the water companies at the sources of supply, seeing how many causes of pol¬ 
lution exist between those sources and the consumer. Besides which it must not be for¬ 
gotten that only a very small part of the water delivered by the company is used for 
primary domestic purposes, the great bulk of it being employed for flushing closets^ 
drains, and sewers, for watering streets, and for various manufacturing operations. It 
would, therefore, manifestly be an unnecessarily wasteful application of a tedious and 
expensive process, to do that at the works which can be so easily, so surely, and so much 
more economically done at the point of consumption. 
But after all the most important consideration at the present time is the means of ob¬ 
taining a constant water supply, so that the prolific sources of contamination and of real 
danger to the community, the filthy butts and cisterns, may be entirely abolished. The 
very first step towards the attainment of this object must be made by the public them¬ 
selves ; for it is idle to expect a constant supply while there is the present imperfect 
condition of almost every household service. If, indeed, such a supply were at once 
given to us, it would assuredly fail, for all the water of the Welsh hills would be insuf¬ 
ficient to maintain it. The daily supply of water to London is at the rate of about 30 
gallons per head, whereas experience has proved in many instances that with a well- 
regulated constant service it need not exceed 20 gallons a head. As a matter of 
economy, therefore, as well as of public health, it is high time the consumer should make 
preparation for such a supply, in the way that the Act of Parliament directs, and then 
there would be no difficulty in applying processes of purification at every point where 
the water is used for domestic purposes. 
At the present j uncture it is advisable that all water stored in butts or cisterns should 
be boiled before it is drunk, and, where it is practicable, it should be previously filtered 
through animal charcoal, or charcoal associated with proper compounds of iron; and, 
failing this, it may be treated with a little of Condy’s solution of permanganate of pot¬ 
ash, until it retains a very pale but decided tint of rose-red. In all cases, however, it 
should be boiled. 
THE PUKIFICATION OF WATEK. 
Dr. Franklaud has made the following communication to the Kegistrar-General:— 
“ Hoyal College of Chemistry, August 4, 1866, 
“ Sir,—In compliance with your request I have made a special analysis of the water 
supplied by the East London Company, and collected on the 1st instant. The following 
are the results, together with those yielded by the water supplied by the same Company 
on July 1, and on the average of a whole year :— 
