32 



METHOD OF DESTROYING ALG^ IN WATER SUPPLIES. 



Effect of cupper sulphate upon Bacillus typhi at low temperature.^'' 



[Determination made in Petri dishes.] 



Duration of exposure to action of copper sulpliate. 



3 hours . , 

 6 hours . 

 9 hours . 

 12 hours . 

 24 hours 



Tempera- 

 ture. 



° V. 



Check. 



One part 

 copper to 



100,000 

 parts water. 







5 

 5 

 5 



h 



Cokmieg. 



2, 187 



2,646 



1,026 



351 



37 



Culunkti. 

 1,944 



702 



98 







"Experiment conducted in test tubes each contiiining 5 cc. of sterilized water, p:irt of whicli had 

 been previously treated with tlie desired amount of copjjcr sulphate. All tubes inoculated with a 

 3 mm. loop of a culture of JJ. ti/plii of the proper age. 



Effect of copjjer sulphate upon Bacillus coll cultures of earious ayes."- 



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

 cates no growth.] 



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

 been r>rcvionsly treated with the desired amount of copper sulphate. All tubes inoculated with a 

 3 mm. loop of a" culture ^^f B. coli of the ]>roper age. 



Effect of copper salplmte ujion Bacillus coli at different temperatures.^ 



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

 cates no growth.] 



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

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

 3-mm. loop of a 24-hour culture of B. coli. 



