KFFKCT OV COPPER UPON PATHOGENIC BACTERIA. 29 



pr()l»iil)U' that it would also destroy bacteria, and that cholera j^erms 

 and typhoid germs nii<i;lit succuuil) to its action. 



The sterilization of pul)lic water supplies ))y chemical means has so 

 tar seemed an impossibility. Nearly every known substance has been 

 tested, but the hioh concenti'ations recjuired to produce the desired 

 effect, the extreme toxicity of tiie a<,^ents, their cost, or the dilliculty 

 of application, have eliminated all but copper sulphate as a possibility 

 for the present purpose. Accordin<4' to Semmer and Krajewski," a 

 1 to 100 solution of this salt will inhil>it action in infected blood, and 

 septic bacteria can ])e destroyed with a 10 per cent solution. Bolton'^ 

 says that 1 to 500 is toxic, but 1 to 1,000 permits the growth of cholera; 

 1 to 200 and 1 to 600, respectively, produce the same results with 

 t^'phoid, and some of the spore-bearing forms are imaffected at 2 per 

 cent. Green *■ gives 2^ per cent as the amount necessary to kill 

 typhoid in two to twenty-four hours, and Hnds cholera only slightly 

 less sensitive. Israel and Klingman,'' however, Hnd that almost 

 infinitesimal amounts of copper in colloidal solution are fatal to 

 typhoid, cholera, and Bacillu.s coll. There is considerable literature 

 upon the use of copper sulphate as a disinfectant for clothing, bed- 

 ding, cesspools, etc., but it is not necessary to review' it at this place. 

 Sternberg'' found that its germicide power was decidedl}- superior to 

 the corresponding salt of iron and zinc, and demonstrated that it 

 destroyed micrococci from the pus of an acute abscess in tlie propor- 

 tion of 1 to 2(»0. He saj'S, "This agent (cupric sulphate), then, is a 

 valuable germicide and may be safely' reconmiended for the disinfec- 

 tion of nniterialnot containing spores." 



The high percentage of copper sulphate given ])v most of these 

 authorities seems to preclude the idea of its practical use for the pur- 

 pose desired. It should be remembered, however, that these investi- 

 gators were working for a ver}' difierent end, namely, to find concen- 

 trations destructive to bacteria in the presence of large ([uantities of 

 al})uminoid and"fatt3Mnatter. Experiments conducted under similar 

 circumstances have confirmed the above results, ])ut the conditions 

 obtaining in public water supplies are widely different. Here the 

 amount of albuminoid matter is so small that the death point of the 

 t} phoid or cholera organism is lowered tremendously and very dilute 

 solutions of copper are shown to be toxic. The tabulated results on 

 the succeeding pages demonstrate this fact. 



"Semmer and Krajewski, Arch. f. exj). Path. u. Pharmakol., 14: 139. 

 ''Bolton, Rep. of Com. on DisinfectantH, Am. Pub. Health Assn., 1888, j). 153. 

 c Green, Zeit. furHyg., 13: 495. 



«^ Israel and Klingman, Virchon'n Archiv., 147: 293. 



''Sternljerg, Kep. Com. Disinfection, Am. Pub. Health Assn., 1888, p. 38. See also 

 Infection and Immunity, New York and London, 1903. 



