IK) Methods for Exam iiuit ion of Soil Protozoa 



111 the case of the Abergavenny garden soil no clear correlation of 

 this kind was observed ; observations were, however, only made in the 

 summer (June) before and after rain. 



To get an idea of the fauna of a soil very rich in humus, a deposit 

 of black leaf-mould in a wood near Abergavenny was sampled. Here 

 thecamoebae were again very numerous, amoebae were slightly less 

 numerous, and small flagellates and some ciliates.were easily detected. 

 As a further example of a soil rich in organic matter, samples were 

 taken from a sewage bed at Abergavenny. Sewage had been led on 

 to this, and allowed to percolate through. When the samples were 

 taken the bed had dried sufficiently to allow of the deposit being 

 scraped up into heaps ready for removal. Enormous numbers of 

 phytoflageliates (forming a green film on the surface) were present, 

 and thecamoebae and amoebae were very plentiful. Cihates were not 

 uncommon, and the smaller flagellates were fairly well represented. 



As far as these results go, it appears that tlie numerically most 

 important types of soil protozoa are thecamoebae and amoebae. 

 Flagellates and ciliates are relatively rare. Of the flagellates found, 

 it is very noticeable that the larger forms, such as Bodo and Copro- 

 monas and their allies, appear so far to be of very little importance in 

 the active fauna. The most successful soil flagellates are small monads. 

 This is a result which is not revealed by cultural methods, when the 

 larger flagellates assume a much more prominent position. Sherman (14), 

 using a dilution method, found small flagellates to be the most abundant 

 protozoa in the soils wdth which he worked^. Though our observations 

 have not, so far, supported his, we cast no doubt on the substantial 

 accuracy of his results. 



The results of examination of the Broadbalk dunged plot in winter 

 and in summer suggest that normal variations in water content may 

 have a considerable effect on the active fauna of the soil, but in the 

 present stage of our investigations we feel it would be premature to 

 lay too much stress on this point. 



' Cunningham (4) arrives at a similar result. 



