THE MICRO-ORGANIC POPULATION OF THE SOIL 291 



TABLE LXXIX. NUMBERS OF PROTOZOA AND OF BACTERIA PER GRM. OF SOIL 



FREQUENTLY FOUND ON TwO BROADBALK PLOTS. CUTLER AND CRUMP. 



FIG. 28. Daily counts of active flagellates (three species) in Broadbalk Plot 2 

 (dunged) (Cutler and Crump, 73^). The numbers are in thousands per 

 grm., and show a remarkable periodicity. 



The investigations have further shown that the numbers, 

 while fairly regular on a uniform plot of land at a given time, 

 do not remain constant, but vary from day to day. The pro- 

 portion of active forms varies considerably, but on 50 per cent, 

 of the days it exceeds 90 per cent, of the total number. The 

 daily variations of three species of active flagellates on the 

 Broadbalk dunged plot are shown in Fig. 28, and those of the 



19* 



