A simple method of water analysis : especially designed for the use of medical officers of health / by John C. Thresh.

Date:
1897
Catalogue details

Licence: Public Domain Mark

Credit: A simple method of water analysis : especially designed for the use of medical officers of health / by John C. Thresh. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    recommended,—as, for example, the examination of the inside of a well, opening the ground around to examine the drains, &c. If there is any possibility of pollution the water should be considered unsafe. Those desiring further information with reference to this subject should consult the author's work on 'Water and Water Supplies.' The following ab- stract of a paper communicated by me to the British Medical Association in 1894 may be studied with advantage. Of the numerous substances found in potable waters it is now generally admitted that only those of organic origin are a serious source of danger, and that by far the greatest risk is incurred in using water liable to contain certain living organisms, which, when introduced into the system, are capable of producing specific disease. Of the presence or absence of such organisms chemical analysis can give us no informa- ation. The presence of organic matter may be chemically demonstrated, but inasmuch as its nature, whether poisonous or innocuous, is beyond the power of the analyst to reveal, it is obvious that a mere chemical analysis may often be worthless or even misleading. This point cannot be too strongly emphasised, since the popular impression that the chemist, by performing a few mysterious experiments with a water in his laboratory, can pronounce at once whether it is pure or impure, safe or dangerous, is shared alike by the ignorant and the learned, and must be dispelled. All the determinations of the analyst are of more or less importance as an index of the degree of pollution, recent or remote, but their real value can in very few cases be assessed without some previous knowledge of the source of the water. The inorganic constituents can easily be determined,