EFFECT OF" COPPER UPON PATHOGENIC BACTERIA. 29 



probable that it would also destroy bacteria, and that cholera germs 

 and typhoid germs might succumb to its action. 



The sterilization of public water supplies by chemical means has so 

 far seemed an impossibility. Nearly every known substance has been 

 tested, but the high concentrations required to produce the desired 

 effect, the extreme toxicity of the agents, their cost, or the difficulty 

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

 for the present purpose. According to Semmer and Krajewski, a a 

 1 to 160 solution of this salt will inhibit action in infected blood, and 

 septic bacteria can be destroyed with a 10 per cent solution. Bolton b 

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

 1 to 200 and 1 to 500, respectively, produce the same results with 

 typhoid, and some of the spore-bearing forms are unaffected at 2 per 

 cent. Green c gives 2J per cent as the amount necessary to kill 

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

 less sensitive. Israel and Klingman,^ however, find that almost 

 infinitesimal amounts of copper in colloidal solution are fatal to 

 typhoid, cholera, and Bacillus coli. There is considerable literature 

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

 ding, cesspools, etc., but it is not necessar3 T to review it at this place. 

 Sternberg^ found that its germicide power was decidedly superior to 

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

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

 tion of 1 to 200. He says, "This agent (ciipric sulphate), then, is a 

 valuable germicide and may be safely recommended for the disinfec- 

 tion of material not containing spores.'' 



The high percentage of copper sulphate given by 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 very different end, namely, to find concen- 

 trations destructive to bacteria in the presence of large quantities of 

 albuminoid and fatty matter. Experiments conducted under similar 

 circumstances have confirmed the above results, but 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 

 typhoid 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. exp. Path. u. Pharmakol., 14: 139. 

 b Bolton, Rep. of Com. on Disinfectants, Am. Pub. Health Assn., 1888, p. 153. 

 c Green, Zeit. fur Hyg., 13: 495. 

 <* Israel and Klingman, Virchon's Archiv., 147: 293. 



^Sternberg, Rep. Com. Disinfection, Am. Pub. Health Assn., 1888, p. 38. See also 

 Infection and Immunity, New York and London, 1903. 



