Abstract
THE Health Congress of the Royal Sanitary Institute, which was held at York during the week ending August 3, was attended by a large number oi delegates. Although but few new scientific facts were brought to the notice of the meetings, many papers of great interest and value to the public health student and worker were read, and some useful discussions followed. Reference should also be made to the general appreciation of special addresses by the. President (the Archbishop of York), Prof. Karl Pearson, and Prof. Henry Kenwood. The following communications may claim a special scientific interest. Dr. Myer Coplans exhibited an instrument, which is an application of the form of ohmmeter which has been in use for many years for testing electrical installations, for the purpose of obtaining the conductivity of liquids. The conductivity of pure water containing an electrolytic substance in solution being due almost wholly to dissolved matter, it is possible, in very dilute solutions, to estimate the percentage amount of substances in solution. By such means it was demonstrated that a fairly ready method is afforded for testing variations in the condition of public water supplies, more particularly the effects of sewage pollution, water softening, the presence of metals (such as lead, iron, or zinc), and the ability of water to take into solution dangerous metals when placed in contact with them for any given period, the addition of water to milk, &c. Dr. Coplans in another paper dealt with some points in the purification of water, in which he pointed out that as all particles in suspension, bacteria included, show, with efflux of time, a tendency to agglutination, and the newly formed aggregates slowly sink, if at any time during the process of agglutination the so-called bacterial counts are made by the usual.methods, the results show a considerable reduction of the organisms originally present, although in reality there is no reason to presume the death of a single organism; for if a number of organisms be aggregated into a single mass the result of “plating,” followed by incubation, is but a-single colony. He concludes that the number of colonies developing,;as the result of “plating,” followed by incubation, is evidence solely of the number of distinct masses of organisms pre-existing; there is no relationship established as to the total number of organisms originally present; furthermore that the methods available for the isolation and recognition of disease-producing organisms in water are so faulty as to be altogether untrustworthy, in so far as negative results are concerned. In this connection he refers to the experiments undertaken at the laboratories of the Metropolitan Water Board, in which in 66 per cent, of the samples intentionally polluted with millions of germs of typhoid fever it was impossible to recover or to recognise the dangerous organisms. He concludes that with such glaringly defective methods for the detection and recognition of dangerous pollution, it becomes increasingly necessary to guard jealously the purity of our water supplies, a proposition which involves an important corollary, namely, the effective control and disposal of domestic sewage and slop-waters. Mr. A. G. Ruston, dealing with the subject of “Air Pollution by Coal Smoke,” directed attention to the difference between domestic and boiler soot obtained from the same coal, domestic soot being characterised by its relatively high content of tar and volatile substances and its low content of ash. He furnished experimental evidence that for every ton of coal purchased by the average householder, one hundredweight goes up the chimney unconsumed, while so far as the factory is concerned there is at least a loss of one stone out of every of coals. In one district of Leeds, the centre of one of the chief industrial areas, he finds that fully 40 per cent, of sunlight during the year of his investigation was shut off by the smoke in the atmosphere, and that the solid impurities which reached the ground as the result of coal combustion amounted to the high figure of 1565 Ib. per acre.
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The Recent Congress of the Royal Sanitary Institute at York . Nature 89, 590 (1912). https://doi.org/10.1038/089590a0
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DOI: https://doi.org/10.1038/089590a0