rorr] DACHNOWSKI—CRANBERRY ISLAND 13 
residual by-products of an incomplete disintegration of peat. 
They unquestionably reduce oxygen-containing compounds in 
contact with them; their action is most marked where micro- 
organisms play a part in decomposing organic matter; the amount 
reaches, it seems, a maximum in early autumn. It should be 
stated further that toxicity and the reducing action of peat soil 
and that of the decomposing organic matter which retards oxida- 
tion in the soil are not necessarily the same phenomena. An 
increase in the amount of oxygen does not always decrease toxicity 
or the reducing power of the soil, and hence the amount of oxygen 
absorbed cannot be taken as the measure of the total action of 
these conditions. 
Reduction processes are predominant in the early stages of 
peat formation, but are less manifest as the concomitant plant 
societies are succeeded by others, and especially when deciduous 
forests prevail. The same factors which decrease the toxicity of 
the habitat and the accompanying reducing processes favor an 
increase in the rate of oxidation and influence thus the character 
and nature of the succession. The greater oxidation, therefore, 
in the known productive peat soils would seem to be due to the 
activity of a different set of microorganisms, which by enzymotic 
action or otherwise hasten the formation of compounds of an 
assimilable nature. The excessive oxygen avidity of peat soils 
in the early formation stages must undoubtedly be injurious to 
plants, unless the plants, indigenous or invaders, are likewise able 
to exhibit oxidizing or reducing powers. The reducing processes 
in a soil very likely activate oxidative powers in plants. The 
various reactions of fungi, micorhiza, alder tubercules, bacteria, 
and the roots of higher plants growing in peat and humus soils 
should on that account be made the subject of considerably greater 
and more detailed study. The consideration of the relation 
between plant societies, relative physiological aridity, and micro- 
Organisms, with their reductive and oxidation processes in soil 
has scarcely passed beyond the theoretic field of speculation. 
And yet it is this relation which makes soil problems especially 
interesting and in need of experimental work of considerable 
scope (28). 
