100 
WHAT IS IN* THE WATEH ? 
botli cases are identical, but the conditions affecting the purity of the water 
as drawn for use are different. A well is subject to contaminations which 
cannot affect a spring. The water as it gushes from the rock, if the source 
be pure, will be free from external contamination, and the constant flow will 
keep it in this state ; but the well may receive something from without which 
is either corrupt or corruptible, and which may render what otherwise would 
be good unfit for use and dangerous to health. 
Tlie question is now frequently asked, What water should we use for 
drinking? The wells in London and other large towns have frequently been 
found to be contaminated with sewage, and the water has sometimes be¬ 
come so dangerous to health from this cause that peremptory measures have 
been adopted to prevent its use. In most, if not all cases, the water of the 
shallow wells of London contains products of the decomposition of animal 
and vegetable matter derived either from the sewers or the surrounding soil, 
and although we believe this is generally, from oxidation or other causes, in 
such a state as to be incapable of causing injury to health, yet occasionally it 
has been found to be otherwise, and in some instances it has been clearly 
shown that the spread of cholera has- been caused by the use of impure -wnll- 
water. 
In an article published in the last number of this journal, Mr. Simon, the 
Medical Officer of the Privy Council, says—“ In relation to Asiatic cholera, 
as now threatening us, there are two principal dangers against which extreme 
and exceptional vigilance ought to be used. First, there is the danger 
of drinking-water which is in any (even the slightest) degree tainted by 
house refuse or other like kinds of filth; as where there is outflow, leakage, 
or filtration from sewers, house drains, privies, cesspools, foul ditches, or the 
like, into streams, springs, or wells, from which the supply of water is drawn, 
or into the subsoil in which the wells are situate,—a danger which may exist 
on a small scale, as at the pump or dip-well of a private house, or on a large 
scale, as in the sources of supply of public waterworks. And, secondly, there 
is the danger of breathing air which is made foul with effluvia, from the same 
sorts of impurity.” 
Again, in some remarks appended to a return representing the quality of 
the metropolitan waters in Jul}'- of the present year, furnished by the Metro¬ 
politan Association of Medical Officers of Health (-which will be found at page 
172), it is stated—“ It is very probable that the most perfect processes of 
purification, so far as they can be used at the works of the water companies, 
will never be sufficient to ensure such a purity of water as the complete removal 
of those subtle agents of disease which even the most refined appliances of 
the chemist have failed to discover. It may therefore well be that all dis¬ 
coverable traces of organic matter may be removed from water, and yet it 
may still contain enough of the'minute germs of disease to manifest its morbific 
action whenever it is used. Experience, indeed, teaches us that it is not the 
quantity of organic matter in water so much as its quality which determines 
its dangerous properties ; and if it be true, as modern pathological science 
has almost demonstrated, that the real agent of such diseases as infectious 
fevers, cholera, the rinderpest, and other allied zymotic maladies, are living 
germs, and not a gas or vapour, or dead organic miasm, it must rest with 
the physiologist rather than with the chemist to decide on the means which are 
best suited to their destruction ; and it is more than probable that the chemist 
w^ould be putting forward very dangerous propositions if, by relying on his 
science alone, he ventured to dogmatize on so difficult a subject.” 
With these statements from the best authorities before us, how can we 
answer the question so frequently asked, Is the water we are accustomed to 
drink a good, wholesome, and safe water to use for that purpose ? It is very 
