Relation to Factor Limiting Bacterial Activity in Soil. 451 



Bacteria in millions per gramme. 





At begin- 



After 



After 



After 



After 



After 



After 



After 





ning. 



32 days. 



60 days. 



93 c 



Lays. 



125 days. 



151 days. 



173 days. 



208 days. 



Untreated (U.) ... 



14-4 



10 -3 



13 



11 -4 



9 





12 



13 -5 



8 



Toluened (T.) 



9 -2 



73 



60 



61 



48 



40 



53 



49 ' 



T. + U 



11 -3 



49 



6L 



43 



70 



19 



39 



45 



m i /"i ; i ■ „ j 



4 *5 



371 



292 



296 



181 





56 



70 



64 





3 



285 



185 



141 



188 





74 



72 



90 



T. + Jblagellates ... 



27 



247 



214 



227 



368 





196 



108 



104 





2 - 3 



500 



341 



311 



296 





181 



196 



151 





After 



After 



After 



After 



After 



After 



After 





259 days. 



301 days. 



337 d 



lys. 



350 days. 



386 days. 



454 days. 



487 days. 



Untreated (U.) ... 



6 



13 



lost 





8 





13 



12 6 



12 



Toluened (T.) ... 



42 



55 



70 





67 





43 



51 



56 



T.+U 



23 



39 



44 





51 





33 



33 



48 



T. + Ciliates 



59 



57 



65 





59 





57 



57 



73 



T. + Amoebae 



57 



65 



68 





62 





50 



41 



57 



T. + Flagellates ... 



77 



104 



92 





94 





81 



35 



113 





116 



151 



85 





105 



138 



115 



150 



32 60 93 125 151 173 208 258 301 337 350 386 454 487 



DAYS 



Fig. 6. 



out of account for the moment the high bacterial counts during the first 

 125 days and the drops at about 150 or 170 days in all three cases, we may 

 say that the protozoa added to the toluened soil in each sample have not 

 reduced the bacteria to a level lower than that of the toluened soil alone. 

 Judged in relation to the protozoa in these soils this is a very instructive 

 result. The T. + Amoebae contained at the end of the experiment 10,000 

 amoebae, perhaps more, and about 5000 flagellates per gramme. The 

 T. + Flagellates contained 10,000 flagellates, perhaps more, and about 

 1000 amoebae per gramme, whilst the T.-f Ciliates contained about 3000 each 

 of Col. steinii and Col. maupasii, about 500 Col. cucullus, and about 1000 



