11)07.] 



PUBLIC DOCUMENT— No. 33. 



173 



of water, while tlie other jar was left untreated. The jars 

 were placed side by side in the laboratory, and exposed to 

 the organisms of the air. The water was taken from the 

 pond previous to its being treated. The results of the experi- 

 ments are shown in the following table : — 



Table shoiving the Besnlts of treating Pond Water with Copper Sulfate 

 at the Rate of 1 Part of Copi^er Sulfate to 4,000,000 of Water. 

 (^Experirnent made in Laboratory , in Glass Aquaria Jars.) 



[Number of bacteria per c. c. of water.] 



June 14, 

 15, 

 16, 

 17, 

 18, 

 19, 

 20, 

 21, 

 22, 

 23, 

 24, 

 23, 

 26, 

 27, 



29, 



30, 



July 1, 



2 



3, 

 4, 

 5, 

 7, 

 9> 

 11. 

 13, 

 15, 

 17, 

 19. 



Date. 



Pond Water 

 untreated. 



7,158 

 5,723 

 4,849 

 4,849 

 4,444 

 6,188 

 7,927 

 6,112 

 4,772 

 6,362 

 5,313 

 6,273 

 7,004 

 6,927 

 8,282 

 8,926 

 6,419 

 7,004 

 7,409 

 8,107 

 6,792 

 7,972 



10,168 

 6,412 

 6,989 

 7,399 

 6,034 

 8,632 



10,656 



Pond Water 

 treated. 



301 



15 



38 



32 



24 



31 



43 



59 



101 



120 



54 



134 



1-26 



98 



170 



242 



310 



270 



298 



340 



930 



872 



800 



1,060 



1,000 



940 



946 



1,390 



1,210 



1 Ouc hour after treatment. 



