But another point of view, and an important one, which makes the consideration of the hardness of the water of some moment, is that you cannot make good tea with hard water. You can make very much better tea, and very much easier, with soft water than with hard. Then there is another important consideration, and that is that with hard water an immense amount of soap is wasted, and the soap wasted by the use of hard waters in England is certainly worth hundreds of thousands of pounds sterling in a year. That happens in this way. Soap is a compound of certain fatty acids with soda or with potash, and it has the property of making a lather with water, and we are able to clean ourselves much better with soap and water than with water alone. Now, if I take distilled water, containing no mineral matters at all, and drop into it one measure of a solution of soap of a certain strength, it produces at once a permanent lather, so that this distilled water takes simply one measure to produce a permanent lather, anfl a small quantity of soap is therefore all that is required. But if I take water containing mineral salts, those mineral salts will decompose the soap, and the lime, magnesia, iron, etc., will combine with the fatty acids and form an insoluble mass which will not lather with water, and so I have to go on putting soap into this water until all the mineral salts have decomposed all the soap they can, and after that the water will lather, and, in this instance, you see that seventeen times the amount of soap is required to produce this result with the same amount of water, and even now it is scarcely a permanent lather.

The organic matters that water contains in suspension and solution are of much greater importance than these mineral salts. It has been known for a very long time that the water of marshes, when drunk, produces intermittent fever, and that the ague of marshy countries is partly caused by drinking the water of the marshes.

Hippocrates himself the father of medicine, points out that persons living in marshy countries are liable to have large spleens, which is one of the results of intermittent fever. I can give you a very remarkable instance of this. Three ships started from a place called Bona in Algeria, having 800 soldiers on board-one ship with 120 men. These started from Bona to go to Marseilles. On that ship 13 men died, and of the 107 left, 98 landed at Marseilles with intermittent fever. The other two ships had no cases, and it was found out afterwards that the water was taken for that ship from the district round Bona, and that district is very marshy and intermittent fevers are extremely prevalent there to this day. It was still further found out that the sailors on board this ship did not suffer at all, and they were supplied with water which the ships had on board before. It is quite conclusive that those soldiers got the intermittent fever from the marsh water.

Water that has been obtained from a marsh contains a large quantity of organic matter in suspension and solution, and it is to this, or some part of it, that the disease is attributed.

In 1849 Dr. Snow drew attention to the fact that cholera was spread by drinking water containing the poison of the disease ; and after that, in 1854 the celebrated case of the epidemic of cholera in and about Broad Street, Westminster, was investigated, and the results published in a report which, one would think, left nothing to be desired for logical accuracy.

These researches showed that the persons in that neighbourhood who were supplied with water from the pump in Broad Street suffered from cholera, and deaths were almost entirely amongst those persons at the beginning of the epidemic. After the pump was closed the cholera did not disappear at once but after a short time ; and an -additional proof that this water was the cause of the cholera was afforded by the fact that some persons who went away from the locality, in order to avoid the cholera, to Hampstead and other places, so believed in the water that after they left the neighbourhood they had the water from the Broad Street pump sent to them in bottles, and those persons were the only persons in those particular localities who suffered from cholera. It is only fair to tell you that even this proof has been doubted by the great German hygienist, Dr. Pettenkofer, who, for certain reasons, throws doubt upon the results drawn from the circumstances I have just sketched out.

However, since that time an epidemic of cholera in the East of London was traced by Mr. J. Netten Eadcliffe to drinking water which had not been filtered, and which was shown to have been polluted with discharges from a cholera patient. It has also been shown by Mr. Simon that when two companies delivered water taken from the same source low down in the Thames, the cholera death-rate among people supplied with water by those two companies was practically the same; but when one of these companies moved higher up, and took the water from a less polluted part of the Thames, during the next epidemic, while the death-rate among the people still supplied with water taken from the lower part of the river was very great, that among those supplied from a higher source was very much lesa Glasgow was formerly supplied with very impure water, and during the cholera epidemic of 1832, 2842 deaths occurred; and in that of 1854, no less than 3886. Pure water was then supplied to Glasgow from Loch Katrine; and in 1866, the next cholera year, in that town, instead of 3886 deaths from cholera, there were only 68.

It has been shown in other places, in Berlin, for instance, that the death-rate in houses supplied with impure water is very much higher than in houses supplied with pure water.

So cholera is spread by drinking impure water!

Typhoid fever is a disease which we have come to know much more about of late, and an immense amount of evidence has proved that this fever is spread by drinking water containing sewage.