62 DACHNOWSKI: BoG VEGETATION AND PEAT SOILS 
growth rate, shows the inefficiency of the usual analytical methods 
of the organic chemist. Neither the properties, the chemical 
formula, nor their effect upon transpiration, alone afford an indica- 
tion of their physiological importance. In addition new analyses 
of peat, wood, and of bog plants from various zones with reference 
especially to the ratio between the carbon and nitrogen content, 
are much to be desired. A study of the relative toxicity of the 
substratum is not independent from a study of the energy needs of 
the organism. Both are equally important and must be ap- 
proached from the point of view of the possible absorption and 
transformation of the compounds or their neutralization into 
insoluble, impermeable compounds, and the specific structural and 
functional peculiarities in plants enabling the change. 
Aside from the nutritive inequalities of organic peat soil con- 
stituents it is worth while to study more closely the various struc- 
tural modifications that appear in plants indigenous to the habitat, 
in the less fit invading plants, and in those which survive. In 
another paper the writer has shown that the phenomena of ab- 
sorption and tolerance of plants in bogs deal with consideration 
of the permeability of the absorbing protoplasmic membrane, its 
power of endurance and its ability either to absorb and assimilate 
or to transform injurious bodies into impermeable compounds. 
The form of invading plants is frequently altered, as is shown by 
dwarfing, the reduction of number and size of leaves, the loss 
of buds and branches, and the rapid aging of the plants. This 
indicates the extent to which the various functional mechanisms 
involved, such as absorption, conduction, and growth, are inter- 
related and coordinated. Every green plant is undoubtedly able 
to a certain extent, to assimilate nitrogenous and other organic 
compounds. Plants that grow preferably on humus and peat soils 
must have special absorptive powers, but little is known, as yet, 
to what extent the roots themselves exert a direct solvent action, 
enzymatic or otherwise, in rendering the peat available for assimila- 
tion, and how far fungal mycorhiza, which form symbiotic unions, 
are of importance. 
The possible scope of this study has been barely indicated. 
BOTANICAL LABORATORY, 
Oxn10 STATE UNIVERSITY. 
