58 



Sfuilies oil Sdi/ Protozoa 



contains protozoa adapted to a tomperature of about 30" C. and that 

 these become active wlieii tlie conditions are favourable for their 

 growth. 



Table 7. 



(ii) On the kind of protozoa in soils. Observations on cultures 

 (chiefly bloodmeal solutions t K2HPO4) of soil protozoa kept at various 

 temperatures have jaelded some interesting results. In such cases at 

 temperatures below 8° C. flagellates only have been observed. These 

 appear to multiply much more rapidly at the low temperature than 

 they do at 22° C, for example, and they continue for a much longer 

 period in the active form. In cultures kept at 22° C. flagellates, ciliates 

 and amoebae may all be present. At 30° C. on the other hand the 

 fauna of culture solutions consists practically entirely of ciliates. A 

 few flagellates are sometimes observed at first. At 38° C. few protozoa 

 develop. Only amoebae have been observed. These points are of 

 importance from the point of view of securing pure cultures of the 

 respective groups. 



As to the effect of temperature on the kind of organisms leading 

 an active life in soil, little definite information has been obtained. 

 Ciliates (in addition to flagellates) have been observed directly under 

 the microscope in droplets taken from the surface of a saturated soil 

 kept at 30° C. The forms seen belonged to the genus Balantiophorus. 

 Such organisms may, therefore, be of importance in sewage and water- 

 logged soils during hot summer weather in temperate climates and also 

 in the rice-fields of tropical countries. 



