30 METHOD OF DESTROYINfi ALGiE IN WATER SUPPLIES. 



Effect of copper sulphate tipon Bacillus ti/phi at different tempemlares." 

 [Determination made in tubes of bouillon, -f indicates growth after 48 hours' incubation; 



cates no growth.] 



indi- 



Duration of exposure to action of copper 

 sulphate. 



2 hours . 



4 hours . 



Tempera- 

 ture. 



6 hours . 



12 hours . 



°C. 

 38 

 28 

 23.5 

 14 



4 

 38 

 28 



23.5 

 14 



4 

 38 

 28 

 23. 5 

 14 



4 

 38 

 28 

 23. 5 

 14 



4 



Check. 



+ 

 + 

 + 

 + 



+ 

 -t- 

 -I- 



-r 

 -f 

 -r 

 -t- 



-I- 

 -1- 

 -f 

 + 

 + 



-f 



1 part cop- 

 per sul- 

 phate to 



100,000 

 parts of 



water. 



+ 

 + 

 + 

 -t- 



(?) 



-t- 



-t- 

 + 



1 part cop- 

 per sul- 

 phate to 



200,000 

 parts of 



water. 



1 part cop- 

 per sul- 

 phate to 

 500,000 

 parts of 

 water. 



(?) 



-I- 

 + 

 -t- 

 + 

 + 

 + 

 -I- 



+ 

 -f 



-f- 



-h 

 -f- 

 + 



-t- 



-I- 

 -f 

 -I- 



-I- 

 -I- 

 -f- 

 -1- 

 + 

 -1- 

 -I- 

 -I- 

 + 

 + 



+ 



+ 

 -I- 

 + 

 -f 

 -t- 

 + 

 + 



aExiieriment 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 a 24-hour culture of B. typhi. 



Effect of copper sulphate upon Bacillus typhi cultures of various agesJi 

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

 cates no growth.] 



Duration of exposure to ac- 

 tion of solution of 1 part 

 copper sulphate to 100,000 

 parts of water. 



3 hours. 

 6 hours. 

 9 hours. 



Culture 36 



hours 



old. 



-I- 

 (?) 



Culture 24 



hours 



old. 



-I- 



Culture 18 



hours 



old. 



Culture 12 



hours 



old. 



+ 



Culture 6 



hours 



old. 



Culture 3 



hours 



old. 



a Experiment conducted in test tubes each containing5cc.of sterilized water, portions 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. typhi of the proper age. 



Effect of copper sulphate on Bacillus typhi at different temperaiures.a 



[Determination made in Petri dishes.] 



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

 had been previously treated with the proper amounts of copper sulphate. AH tubes inoculated with 

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



