58 MISCELLANEOUS PAPEBS. 



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

 have apparently established the point that copper sulfate will not 

 destroy 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 desiral)le 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 t3^phoid 

 organisms; in other words, that many bacteria which could be of 

 decided benefit in a slightly polluted water supply might be eradicated 

 b}^ copper treatment and that in this way the fractional sterilization of 

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

 tamination. 



Investigations of these and other points have been undertaken, and 

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

 copper treatment for algae, to emergency treatment for t^^phoid, and 

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

 ment of sewage may be influenced by 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 sufficiently accurate for practical 

 purposes. 



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

 uniform emulsion of 8 cc. of liquid to one 48-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 amoebae or cholera." 



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

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



Jackson. Journal New England Water Works Association, vol. 19, 1905, 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 Eeports, 

 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 that 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 * * -s^- 

 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 



