INFLUENCE OF EARTHWORMS ON SOIL REACTION. 419 
Hence any difference of reaction between surface soil and wormcasts may 
safely be attributed to earthworm action. The data respecting the hydrogen- 
ion concentration given in Table III. and fig. 2 show that in the majority 
of localities the wormeasts exhibit a marked reduction in acidity (increased 
pH) as compared with the soils from which they are derived. 
The detailed determinations need not be given in extenso, but two examples, 
the one from an acid location, the other from an alkaline, will suffice to show 
the kind of range to be expected in a given area, the soil samples in all 
cases being taken from the actual level at which the worms were found 
feeding. 
Tage IV. 
Details of Reaction in Two Locations. 
A. Acid Soil with Festuca rubra dominant and Agrostis canina. 
No. of No. of 
pH Values. Soil Samples. Wormcast Samples. 
Sl auuaeeaasraar rrr ] 
D cee ae 6 
A 1 
O ET EEE 0 
O . 1 
56 n 1 3 
5 Illis — 3 
DB E — — 
59 .lleeeeeee rrt — 2 
6:0 ,,,,................ — 2 
Gl ouuusarerseeser rrn © — 2 
62 eee cece eee eee eee oo l 
Total Samples ...... 10 (Av. pH 527). 13 (Av. pH 584). 
B. Alkaline Alluvial Soil under mixed herbage. 
No. of No. of 
pH Values. Soil Samples. Wormeast Samples. 
TÀ Velle hen — 1 
TOÀ Be — 3 
TA. Scr eee wees 4 4 
T5 llle 9 — 
Total Samples ...... 6 (Av. pH 7745). 8 (Av.pH 7:33). 
The first and most important fact which these data establish is the con- 
siderable change in the reaction of acid soils effected by the earthworms, 
amounting to 0°75 pH in one instance. The change in reaction will be 
more readily appreciated if the differences in the negative logarithmic values 
given in Table ITI. are presented in the form of specific acidities (cf. Table V.). 
These show that the effect is more marked the more acid the original soil, 
and that whereas the acidity of the soil is almost invariably decreased, the 
effect on alkaline soils may be to diminish the alkalinity (Table IV. b & fig. 2). 
