Grains per gallon

" Chloride of sodium (common salt)

. 1330.0

Chloride of calcium

1110

Chloride of magnesium ...

91.2

Carbonate of sodium

10.0

Total ...

. 1512.2"

The next sample is drawn from the wells in the chalk at Croydon, and is noteworthy for the large amount of carbonate of lime it contains.

Grains per gallon.

Silica

... 1.2

Carbonate of calcium

... 17.8

Carbonate of magnesium ...

11

Chloride of sodium

2.0

Sulphate of sodium

... 0.9

Total ...............

... 23.3"

This is a very hard water.

The sample which gave the following analysis is from Sudbrook Springs under the Severn: .

Grains per gallon.

" Carbonate of calcium

... 13.6

Carbonate of magnesium ...

... 5.1

Sulphate of magnesium

... 3.2

Nitrate of magnesium

... 0.6

Chloride of magnesium

08

Chloride of sodium (with a little potassium)

... 3.5

Total ..............

... 27.1"

Besides a considerable amount of chalk, this water is noticeable for the number and variety of the salts of magnesia it contains. It is therefore classed with the magnesian waters.

On the other hand, water collected from formations which are mainly composed of insoluble rock, are naturally remarkable for their freedom from saline constituents, as the two analyses of Woodland and Holm. firth waters will show.

"Manchester Water (Woodland)

Grains per gallon.

Silica

... 0.30

Carbonate of calcium

1.70

Sulphate of magnesium ...

1.66

Chloride of sodium

0.91

Total ...............

4.57

Holmfirth Water

Grains per gallon.

Sulphate of calcium

... 0.8

Sulphate of magnesium ...

... 0.6

Chloride of sodium

... 0.8

Nitrate of sodium or potassium ...

... 0.2

Total ...............

... 2.4"

The above specimens of water are obviously extremely soft, and under ordinary conditions of water.supply the fluid is divided into two kinds, hard and soft water, the hardness being clue always to the lime salts . chiefly carbonate of lime or chalk, with the addition of a small quantity of the sulphate. Specimens of water containing large quantities of a great variety of mineral matters are properly classed as medicinal waters, which, however valuable in dealing with certain forms of disease, are not fit for use for dietetic purposes.

The question of the influence of hard water upon health has been frequently debated, and various opinions have been given in reference to it. There is no doubt that hard waters are constantly used for drinking purposes without any harm being suffered by the persons who take them, but it is asserted, by the author of the article from which we have quoted, that horses drinking hard water suffer from derangement of the organs of digestion, indicated by attacks of colic and other intestinal disorders. The skin is also said to lose its polish and become dull and scurfy, the coat stares, and a general state of unthriftiness is induced. These results, however, suggest a very abnormal degree of hardness in the water which produces them. They are certainly not observed among horses which are living in chalk districts, where the use of hard water for men and also for the lower animals can hardly be avoided. Generally where hard water is distributed by the water companies it undergoes a preliminary process of softening by the addition of lime, which converts the soluble bicarbonate of lime into the insoluble carbonate or chalk, which is precipitated, and in this manner a considerable quantity of the lime is got rid of. The process, however, cannot be adopted on a small scale, where hard water is stored in tanks or ponds.

Hard water has occasionally been referred to as a cause of diseases of bone and the formation of calculous concretions. It may be remarked, however, that the hardness of water is chiefly due to carbonate of lime, and would not, therefore, be likely to be very largely concerned in the formation of bony tumours, in which the phosphate of lime is the chief constituent; but there is no doubt that lime salts would be likely to contribute to the formation of calculous deposits in the digestive system or in other parts of the body.

It has already been stated that water forms a very large proportion of the tissues of the animal body - from 70 to 80 per cent, - and in the lower forms of living beings it may reach as much as 90 per cent. Professor Axe, in his articles in the Royal Agricultural Society's Journal, has given the following table, showing the amount of water contained in 1000 parts of the various organs and structures: -

Kidneys

827

Heart

792

Nerve

780

Spleen

758

Muscle

757

Sweat

995

Saliva

995

Tears

982

Brain

750

Skin ......

720

Bone marrow

697

Liver

693

Cartilage

550

Gastric fluid

973

Milk ......

891

Fat ......

299

Bone

216

Ivory ......

100

Enamel of tooth ...

2

Bile ......

864

Blood ......

791

The supply of water to the system is introduced in various ways, but the larger proportion is taken in the form of liquid or solid food, and there is also a certain quantity of water formed in the system by the oxidation of the various organic substances, resulting in combinations of oxygen with hydrogen and carbon producing water and carbonic acid.

Considering the important uses to which water is destined in the animal organism, it is remarkable that there is so little positive evidence of the injurious results attending the consumption of water which is polluted with animal and vegetable matter in various states of decomposition, with leakage from drains, with constant admixture with animal excreta, with the gases which are given off from decomposing bodies, and also with the organisms of specific diseases. It is quite true that every now and then the public is startled by a record of a great outbreak of typhoid fever or other fatal disease in consequence of some accidental contamination of the water-supply; but, as a rule, polluted water is about the last thing which is thought of as a possible cause of the outbreak of disease. This indifference probably arises in a great degree from the knowledge of the fact that people and animals continue to use the water of wells which are so placed as to be open to the entrance of the overflow of cess-pools; or, in cases of great scarcity, water from roadside ponds or ditches which are open to every possible source of contamination, not only from causes which have been referred to, but from the addition of various kinds of offal not merely from healthy animals but from those which have died of anthrax, swine-fever, tubercle, and various other maladies. In addition to these sources of serious pollution there are the products of various kinds of manufactures. In mining districts the streams become contaminated with various poisonous substances; such manufactories as linen and jute works, starch factories, cloth works, tanneries, paper factories, and, in short, all kinds of manufactories which deal with organic substances in any form and discharge their refuse into ditches, or ponds, or rivers, or even on to the surface of the ground, through which they soak, contaminate the water springs at their sources.