62 



Sfitffies OH Soil Protozoa 



these results confirm those of Experiment III. The saturated sample 

 in Experiment IV has again shown a great increase in the numbers of 

 protozoa. 



Table Jl. 



Dilutions 



Total Numbers 



Bac- 

 teria 



The increase in the bacterial content of the saturated sample as 

 compared with the bacterial content of the 70 % sample at the beginning 

 of the experiment is again probably due to the protozoal activity having 

 passed its maximum. The increase in the bacterial numbers in the 70 % 

 sample during the course of the experiment was only to be expected 

 from what has already been deduced. 



(ii) On the kind of jwotozoa in soils. In the cultures made from the 

 dilutions, considerable variations are to be observed in the kind of 

 organisms obtained from saturated, 70 % w.H.c. and dry soils. In 

 cultures from saturated soils practically only flagellates are found. 

 The 70 % and dried samples on the other hand yield amoebae in 

 addition to flagellates. Ciliates are seldom seen in any of the cultures. 

 It seems highly probable, therefore, that the flagellates may require 

 a rather moist medium for the unfolding of their activities. The 

 amoebae appear to prefer a somewiiat drier soil. But it is possible 

 that they may also lead an active life in saturated soils but may be 

 suppressed in the cultures li\- tlie fliigcllntes wliidi arc ])res('nt in large 

 numbers in such soils. 



