Text-book of hygiene : a comprehensive treatise on the principles and practice of preventive medicine from an American standpoint / by George H. Rohé and Albert Robin.

George Henry Rohé

Date:: 1908

Credit: Text-book of hygiene : a comprehensive treatise on the principles and practice of preventive medicine from an American standpoint / by George H. Rohé and Albert Robin. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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$000 gallons per acre per day, if the raw water is passed, previous to filtration, tlirongh a preliminary filter, which removes about 50 to 75 per cent, of the turbidity and bacteria. Following the remarkable demonstration of the efficiency of slow sand-filtration in removing cholera bacilli from the water, sand-filters were installed in almost all the large cities of Europe, and wherever installed have reduced t^^phoid mortality to a very small percentage. In this country, the first slow sand-filter was built by Kirk- wood, in Poughkeepsie, N. Y., in 1877. This filter, however, was operated without any particular regard to the scientific aspect of fil- tration, and under disadvantageous climatic conditions. The first filter which has contributed very largely to our know- ledge of the subject, and which has served as a model for other plants, is the slow sand-filter constructed in Lawrence, Mass., in 1893. This filter has been in operation ever since, giving excellent results both as to the improvement of the polluted Merrimac water and the reduc- tion of the typhoid mortality in the city. This is shown in the fol- lowing table:— Table XI. Death Rate Per 100.000. Year. Before Filtration. Year. After Filtration. 1885 42.0 1893 86.6 1886 57.5 1894 50.0 1887 117.5 1895 18.6 1888 120.0 1896 16.2 1889 137.5 1897 13.9 1890 133.3 1898 33.0 1891 122.0 1899 18.1 1892 111.1 1900 18.0 Following the introduction of slow sand-filtration in Lawrence, slow sand-filters have been constructed in a number of American cities, the most notable of which is Albany, ]^. Y. In the latter city a covered slow sand-filter was constructed by Mr. Hazen in 1899. The improvement in the mortality from typhoid fever and diarrheal diseases has been very marked, as shoT\Ti by Mr. Bailey, the superin- tendent, in his report for the year ending 1901:— An examination of the health records of the city shows some interesting features coincident with the commencement and continued operation of the filter, as follows:—$