Water in Relation to Health and Disease. 735 
of such as render it agreeable and useful to the economy. 
Chemically pure water, i.e., water freed from all those substances 
which it derives from the soil and air, is not only impossible in 
nature, but it is at the same time most undesirable as an aliment. 
Many of the mineral substances commonly contained in water 
are when existing in large amount unquestionably hurtful ; but 
some, and especially the salts of lime, potash, soda, and iron, 
when present in moderate quantity, serve, not only to render it 
cool, palatable, and refreshing, but also to supply the system 
with the requisite inorganic constituents of the flesh for the 
growth and renovation of the body. 
Nothing can be said in defence of organic filth, which in the 
form of decomposing animal and vegetable remains so largely 
enters into the water supply of our farm animals. As to pollu- 
tion from industrial sources, this is annually becoming greater 
and more serious as manufactures become more numerous and 
active on the banks of our great waterways. It is not claimed 
that a high standard of purity, such as would be insisted upon for 
human consumption, is absolutely necessary to a high standard of 
health in our lower animals. Their habits and instincts plainly 
and forcibly suggest an organisation capable of considerable resist- 
ance to organic and inorganic contamination of both food and 
water; but it will not be contended that water contamination is 
not a fruitful cause of disease and death in the live stock of the 
farm, for there can be no doubt that animal health like human 
health will rise or fall in proportion as the water supply is whole- 
some or unwholesome. The circumstances of animal life render it 
impossible to gauge even approximately the actual amount of 
sickness and mortality arising out of the use of impure water. 
The evidences of mischief from this cause do not always take the 
form of clearly defined disease, but too frequently of general 
unthriftiness and insidious impairment of health, which by 
diminishing the vital resistance of the system predisposes to 
more definite ailments. Moreover, the capability of the body to 
keep in check and overcome the ravages of “ disease germs ” 
may unquestionably be weakened by the degrading influence of 
impure water. 
Experience teaches that the losses from water contamination 
in one form and another are very considerable, and it may be 
safely affirmed that thousands of animals perish every year from 
the poisons of putrescence, and from parasitic life which abounds 
in foul water, whilst thousands more suffer long-continued 
sickness and prostration from the ravages they produce. That 
animals may and do continue to drink water visibly impure for 
long periods without suffering from any clearly defined disease 
