EFFECT OF COPPER UPON PATHOGENIC BACTERIA. 



33 



Effect of copper sulphate upon Bacillus coli at room temperature. a 

 [Determination made in Petri dishes.] 



Experiment conducted in test tubes, each containing 5 cc. of sterilized water, portions of which 

 had been previously treated with the desired amounts of copper sulphate. All tubes inoculated with 

 a 3 mm. loop of an 18-hour culture of B. coli. 



Effect of copper itulphale upon Bacillus coli at low temperature. a 

 [Determination made in Petri dishes.] 



a Experiment conducted in test tubes each containing 5 cc. of sterilized water, part of which had 

 been previously treated with the desired amount of copper sulphate. All tubes inoculated with a 

 3 mm. loop of a culture of B. coli of the proper age. 



Effect oj copper sulphate upon paracolon cultures of various ages. a 



[Determination made in tubes of bouillon. + indicates growth after 48 hours' incubation; indi- 

 cates no growth.] 



a Experiment conducted in test tubes each containing 5 cc. of sterilized water, part of which had 

 been previously treated with the desired amount of copper sulphate. All tubes inoculated with a 

 3 mm. loop of a culture of paracolon of the proper age. 



These tables show that Bacillus typhi is more sensitive to copper 

 sulphate than is coli, that the para group are about equally sensitive, 

 and that temperature has a very important bearing on the toxicity of 



