Studies in Water Supply |
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0.5 per cent 72 MONTHS ENDED acid Agar at 37 agin April artificially added artificially infected Average number bacteria per c.c. bile-salt bile-salt-agar c.c. cultures c.c. of water cane-sugar chemical cholera vibrios cities coagulant coli test column containing dose dulcite enteric fever experiments fæces filtered filtered water filtration Gärtner Gärtner's bacillus gas formation gelatine glucose hard waters hypochlorite improved incubation indol Infected Sample inoculated isolated June labels lactose lime London Water medium method Metropolitan Water Board microbes microbes per c.c. milk million gallons negative neutral red nitrogen number of bacteria NUMBER OF MICROBES number of typhoid Peptone peptone water pollution Presumptive purification raw river water raw Thames water reduced RIVER LEE RIVER THAMES saccharose Sagin samples of raw sewage Sodium Chloride sterilisation streptococci TABLE Thames water tinted with litmus Turbidity typhoid bacillus typhoid fever typhoid fever rates Typhoid rate typical water supply White wool plug
Popular passages
Page 111 - American cities, and even hi entire states, where the public water-supplies are well guarded from pollution, infection by water has come to be a secondary cause of the disease. In a general sort of way it may be said that in the cities of the United States, at the present time, about 40 per cent of the typhoid fever is due to water, 25 per cent to milk, 30 per cent to ordinary contagion (including fly transmission), and only about 5 per cent to all other causes. In cities supplied with pure well...
Page 98 - An adequately stored water is to be regarded as a ' safe ' water, and the ' safety change ' which has occurred in a stored water can be recognised by appropriate tests.
Page 193 - HOUSTON, AC 1908. The Vitality of the Typhoid Bacillus in Artificially Infected Samples of Raw Thames, Lee, and New River Waters, with Special Reference to the Question of Storage. First Report on Research Work, Metropolitan Water Board, London. HOUSTON, AC 1909.
Page 96 - B. coli to a proportionately greater extent than it does the number of bacteria of all sorts; (г) the color results improve relatively to a greater extent than those yielded by the permanganate test. (3) Storage, if sufficiently prolonged, devitalizes the microbes of water-borne disease, eg, the typhoid bacillus and the cholera vibrio. (4) Storage produces a marked " leveling" or " equalizing " effect. (5) An adequately stored water is to be regarded as a
Page 27 - ... (1) That streptococci are superabundant in human faeces. (2) That faecal streptococci are absent or non-discoverable in a relatively large volume of pure water. (3) That faecal streptococci do not multiply in pure water. (4) That some faecal streptococci are of feeble vitality and that the presence of such streptococci in a water, if they could be differentiated from their more robust companions, would seem to indicate pollution of recent and therefore specially dangerous sort.
Page 131 - ... vital assets." On page 36 he computes, upon what may be regarded a very sound basis, that "each million gallons of polluted Allegheny river water pumped to Pittsburg has heretofore reduced the vital assets of the community by $110. This for a population of 350,000 amounts to $3,850,000 per year — a sum enormously greater than the annual cost of making the water pure.
Page 64 - ... the true import of these facts has only been realized within the last four years. As a practical process it dates from 1908, when Mr. GA Johnson of New York City was called in to remedy some serious trouble in the water purification at the Chicago Stock Yards. The filtered water of Bubbly Creek182 contains a large amount of sewage and it had been purified by a process of filtration in conjunction with copper sulphate, but it was the complaint of the large stock shippers that animals drinking...
Page 98 - The use of stored water goes far to wipe out the gravity of the charge that the chief sources of London's water supply are from sewage-polluted rivers.
Page 190 - Parts per 100,000 into grains per gallon, multiply by 7, and divide by 10. Grains per gallon into parts per 100,000, multiply by 10, and divide by 7. "Hardness...
Page 134 - It was found that one pound of the average soap would soften 167 gallons of water which had a hardness of 20 parts per million. This is equivalent to about three tons of soap per million gallons. It was also found that for every increase of one part per million of hardness the cost of the soap increases $10 per million gallons of water completely softened.