EFFECT OF COPPER UPON WATER HACTKRIA. ()7 



nithcr hii^li toxicity for i-ilciiiin chlorid, aiul of Tfulil,' wlio su^<i('s(s 

 a c-aU-iimi salt— milk of iimo — for water sterilization. The use of lime 

 or a similar ajivnt mav l>e hiiihlv desirable in connection with treating- 

 a contaminated reservoir with copper, though the inferior ^•ennicidal 

 power of lime makes it improbable that the latter alone could be used 

 safely. 



In ivi'-ard to chemical water analysis, it seems proliable that the 

 determination of carl)on dioxid oi' the determination of nionocarbon- 

 ate and ))icarbonate alkalinity may have importance hitherto unrecog- 

 nized, and the variations in the longevity determinations of Ii(ttulh(i<c<>U 

 and BdcilhiK tij]>Ju may be due in part to the mineral constituents of a 

 water, in part to methods of experimentation, and in part to the car- 

 bon dioxid content. Extended field tests nuist be made l)efore <i'en- 

 eralizations on the possible effect of the gas content of a water supply 

 can be determined. 



The carbt)n dioxid content of a watcM' may possibly explain the 

 peculiar results obtaine(l by (Mark and (iage.'' They have reported 

 practically no toxic a<'tion from metallic copper, or at least very little 

 dirt'erence in the action of metallic copper, iron, tin, zinc, and lead. 

 Their figures are rather mish^iding because of the great number of 

 days the experiments were carried on, and, as Phelps'' has shown, 

 metallic copper is coated with some insoluble substance after a few days' 

 exposure to Boston tap water and no longer has great toxic action. 

 The lack of toxicity of metallic copper and the similarity of its action 

 to the action of other metals, as i-eported by Clark and Gage, is 

 entirely at variance with the work of Kraemer, '^ Pennington,'' Gil- 

 dersleeve,-^ Stewart,*^ and Moore and Kellei'man.''' Investigators 

 generally have agreed that it would be possible to practicalh^ sterilize 



« tJber die Disinfection der Typhus and Cholera-ausleerungen niit Kalk. Zeitsehr. 

 f. Hyg. u. Infekt., vol. 6-s, 1S89, pp. 97-104. 



''The Use of Copper Sulphate in ^Vater Filtration. Journal of Infectious Diseases. 

 Supplement No. 2, February, 1906, pp. 172-174. 



<■ Experiments on the Storage of Typhoid Infected Water in Copper Canteens. 

 Public Health Papers and Reports, American Public Health Association, vol. 31, part 

 1, 1905, pp. 75-90. 



''Copper Treatment of Water. American Journal of Pharmacy, vol. 76, December, 

 1904, pp. 574-579. 



The Use of Copper in Destroying Typhoid Organisms and the Effects of Copper on 

 Man. American Journal of Pharmacy, vol. 77, June, 1905, pp. 265-281. 



<^The Action of Electrically Charged Cojiper Upon Certain Organisms in Water. 

 American Journal of Medical Science, vol. 129, 1905, pp. 751-754. 



/Studies on the Bactericidal Action of Copper on Organisms in Water. American 

 Journal of Medical Science, vol. 129, 1905, pp. 754-760. 



6' A Study of the Action of Colloidal Solutions of Copper upon Bacillus Typhosus, 

 American Journal of Medical Science, vol. 129, 1905, pp. 760-769. 



'' Buls. 64 and 76, Bureau of Plant Industry, U. S. Dept. of Agriculture. 



100— VII 



