12 BOTANICAL GAZETTE [JULY 
integrating, however, less readily than that from the maple-alder 
zone. 
The reducing action of peat soil 
It is a well known fact that fresh samples of bog soil upon expo- 
sure to the air extract oxygen from the air with great rapidity. 
Soil-sampling tests show that this power is strong in the cranberry- 
sphagnum peat, reaches a maximum in areas where the peat sub- 
stratum is compact and less coarsely fibrous, and decreases as the 
border zone along the margin of the lake is reached. Judged by 
the quickness with which the soil becomes colored, and the inten- 
sity of the color, reducing processes increase on Cranberry Island 
from any marginal point to the central zone, and decrease as the 
opposite shore is approached. Reduction action becomes greater 
with the depth of the deposit. 
The reducing power of the soils is shown clearly by the addi- 
tion of a starch iodide solution. The observable action is variable, 
as already mentioned; the blue color disappears rapidly in soils 
from the cranberry-sphagnum area; the solution is greatly light- 
ened with soils nearer the margin of the lake; no action is detected 
with soils along the margin. Various dyes such as lacmus and 
methylene blue and other coal tar colors decolorize similarly. 
Possibly the absence of sulphur in the analysis of maple-alder peat 
(table IT) is due to the complete conversion of sulphur to hydro- 
gen sulphide. This gas is the product of a reduction and has been 
detected by means of lead acetate paper. 
Whether the reduction power in peat soils is produced by micro- 
organisms, is due to enzymes, or caused by external chemical or 
bacterial metabolic products, these tests fail to show. Nothing 
absolutely certain is known regarding the composition and the 
nature of reducing substances. They have not at present been 
very fully studied by ecological workers. Apart from their 
destruction by aeration, tillage, and heat, and their adsorption 
by insoluble substances such as quartz, kaolin, carborundum, 
lamp black, and others, uncertainty exists as to whether the redu- 
cing bodies in bogs are unsaturated compounds comparable in 
properties to unsaturated fatty acids, to substances which possess 
the characteristics of certain organic reducing ferments, or to 
