58 MISCELLANEOUS PAPERS. 



In spite of the fact that the field results of several experimenters^ 

 have apparently established the point that copper sulfate will not 

 destro3" ordinary water bacteria at concentrations fatal to the colon 

 and typhoid bacilli, the somewhat fanciful objection has been sug- 

 gested to chemical treatment of any kind, and to copper treatment in 

 particular, that bacteria desirable for oxidation of organic matter and 

 "other beneficial changes in a water supply might be injured equally 

 with the typhoid bacteria, and thus a treated water be more poten- 

 tially dangerous than an untreated water known to contain typhoid 

 organisms; in other words, that many bacteria which could ])e of 

 decided beneiit in a slightly polluted water supply might be eradicated 

 by copper treatment and that in this way the fractional sterilization of 

 a reservoir by copper might pave the wa}^ for a more dangerous con- 

 tamination. 



Investigations of these and other points have been undertaken, and 

 it iiij believed that valuable data have been obtained, applicable to 

 copper treatment for algse, to emergency treatment for typhoid, and 

 to copper treatment in connection with filtration. The copper treat- 

 ment of sewaoe mav be influenced bv the same conditions that bear 

 upon the effect of copper treatment of water. For the present, how- 

 ever, the investigations of Johnson,* at the Columbus, Ohio, sewage 

 testing station may be considered sufficient!}^ accurate for practical 

 purposes. 



to be tested was then added to the 4 cc. emulsion of amcebse, thus making a fairly 

 uniform emulsion of 8 cc. of liquid to one -IS-hour slant culture, the mixture con- 

 taining a definite amount of the chemical to be tested. * * * It would appear 

 from the above results that it would be disastrous to rely on the action of copper 

 containers to purify water infected with amcebpe or cholera." 



« Caird. Copper Sulphate Results. Paper read at meeting of American Water 

 Works Association, Boston, Mass., July 10-14, 1906. 



Jackson. Journal New England Water Works Association, vol. 19, 190.5, pp. 

 563-568. 



Hollis. Journal New England Water Works Association, vol. 19, 1905, pp. 571-572. 



Stokes and Thomas. The Effect of Copper Sulphate upon the Bacteriological and 

 Chemical Constituents of Large Bodies of Water. Public Health Papers and Reports, 

 American Public Health Association, vol. 31, part 1, 1905, pp. 75-90. 



& The Copper Treatment of Sewage Effluents. Report on Sewage Purification at 

 Columbus, Ohio, 1905. 



"Available data indicate tliat the removal by either process of applied pathogenic 

 and nonpathogenic bacteria is in fairly direct proportion, generally speaking, 

 although, of course, saprophytic bacteria may multiply within the tanks or filters, so 

 as to obscure the true removal. Under some conditions it might be advantageous to 

 employ a germicide, such as sulphate of copper, as a final treatment for sewage efflu- 

 ents of doubtful bacterial purity." (P. 471.) 



" Independent of the question of complete sterilization as touched upon * * * 

 it may be that there is a field of usefulness in some places for copper sulphate or other 

 germicidal chemical in the treatment of coarse-grain filter effluents, in order to bring 

 them from a bacterial or hygienic standpoint to a degree of purity strictly compar- 

 able with that of the effluent of ordinary intermittent sand filters." (P. 479.) 

 100— VII - ' 



