264 Dr. H. Chick. The Process of Nitrification [Apr. 1, 



Table V. — Enumeration of Organisms in Filtrates. 



Date. 



Munich con. 

 tinuous filters. 



No. of orga 



Growing in 

 bouillon. 



nisms per cubic < 



Nitrite- 

 producer. 



;entimetre. 



Nitrate- 

 producer. 



Time sub- 

 cultures were 

 kept. 



6.6.03 



Tall 



10,000 



10,000 



100* 



6 weeks 



6.6.03 





1,000 



10,000 



100 



6 „ 



6.6.03 



Short 



100,000 



10,000 



100 



6 „ 



12.6.03 



Tall 



10,000 



10,000 



10,000 



4 months 



12.6.03 





100,000 



100,000 



1,000 



4 „ 



12.6.03 



Short 



100,000 



10,000 



100 



4 „ 



18.6.03 



Tall 



10,000 



10,000 



ioo r 



Former 4 m. 



18.6.03 



Short 



1,000 



1,000 



10 t 



Latter 6 w. 



24.6.03 



Tall 



10,000 



1,000 



10,000 



4 months 



24.6.03 





10,000 



1,000,000 



10.000 



4 „ 



27.6.03 



Tall 



1,000 





10,000 



4 „ 



27.6.03 





10,000 





10,000 



4 „ 



Culture containing O'Ol c.c. filtrate, used for dilution experiment on p. 252. 



Table VI. — Eesults of Inoculating two different Impure Nitrite-producer 

 Cultures, " a " and " b," into Ammoniacal Media, both directly and after 

 passing through one or two generations in bouillon. + + indicates an 

 intense nitrite reaction. 



Series. 



Sequence of inoculation. 



" a," three 

 weeks old. 



" a," twelve 

 days old. 



" b," 

 week 



three 

 s old. 



" b," four 

 weeks old. 



1 



From original material 



+ + 







+ + 



+ + 



+ + 



4 







+ + 



+ + 



+ + 



+ + 





3 



From original through bouil- 















+ + 



+ + 



+ + 





lon (Series 2) 















6 



From Series 2 again, through 





















bouillon (Series 5) 















