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KEEPING WELL |
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quired. Unfortunately, the test is seldom made until disease or death has awakened the community to a sense of the necessity of making it. Typhoid fever in countless cases has been communicated by drinking water contaminated with the germs of the disease. The same is equally true of intermittent or malarial fever. Cows have been seen by the author wading in a stream filled with vegetation upon which they were grazing, this stream forming the water supply of a city about two miles distant. The same stream was alleged to have been infected with sewage flowing from a large public institution nearby. This water was passed through filter beds, but it is questionable whether any filter bed is so perfect as to exclude microscopical germs. It is not strange that typhoid fever prevailed in the community which had this water supply, nor that bacteria which are peculiar to the large intestine in man and animals should be repeatedly found in water which was derived from this source. Many equally flagrant cases would doubtless be revealed, if the water supplies of other communities were carefully investigated. Is not this a sufficient proof that our public water sources cannot be too rigorously protected ?
All our so-called mineral springs contain inorganic matter in solution, and in some of them the quantity is large and materially affects the quality and influence of the water. Water which contains lead, sulphur, lime, iron, magnesia, lithia, etc., is of such common occurrence that it is hardly necessary to mention it, while the water of the ocean contains not only chloride of sodium, or common salt, in abundance, but often bromine, iodine, and other minerals which are useful in some instances and harmful in others.
Water is hard or soft, according as it contains much or little inorganic matter; lime water is hard, rain water is soft. It is commonly stated that water purifies itself of impurities after flowing a certain number of miles. Such a statement is very misleading. It is doubtless true that many substances which are heavier than water are dropped or settled after flowing a greater or less distance, but there is no reason for supposing that substances which are in perfect solution, or which are of a microscopic size, are thus rendered innocuous; indeed, these are |
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