368 BOTANICAL GAZETTE [NOVEMBER 
Aside from the mineral substances composing the ash of such 
bodies, the organic compounds are made up for the most part of 
carbon, hydrogen, and oxygen. In the case of the proteids, there 
are added to these nitrogen, sulfur, and phosphorus. As to the 
exact nature of the compounds existing in the dead material, aside 
from the carbohydrates, very little is. known. The same statement 
holds as to the nature of the decomposition which goes on without 
the intervention of saprophytic organisms. But it seems probable 
that oxidation does occur. This action, then, is the beginning of 
the more comprehensive process known as peat formation. 
When plants or their organs die, under ordinary circumstances they 
are at once attacked by fungi and bacteria. The progress of disso- 
lution is then greatly hastened, and the final disintegration is more 
complete. According to the operation of certain external factors, 
the destruction may involve two very different groups of organisms 
and result in bodies of very different chemical and physical properties. 
These two processes are known as eremacausis and putrefaction 
(61, 39). 
Where access to oxygen is accompanied by favorable temperature 
and moisture conditions, the first of these processes, eremacausis, 
takes place. The formation of ordinary soil humus may be cited as 
an example. That oxygen plays the important réle has been demon- 
strated both by experiment, and by the analysis of the gaseous and 
solid products. It has been shown, for example, that soils i in which 
eremacausis is in progress contain CO, and O in inverse proportion 
to one another. Under constant volume, as the one increases the 
other decreases. It has been also shown by experiment that the 
process is wholly dependent upon the activities of certain lower 
plants. Among these members of the genera Mucor, A spergillus, 
Penicillium, Saccharomyces, Micrococcus, Bacterium, spiilum 
Crenothrix, and Beggiatoa are most important. O, and 
The carbohydrates are by this means broken down to C f rms 
H,O. The albuminoids and amides constitute the principal . 
of the nitrogenous materials. Under the influence of these agit 
especially their katabolic processes, the oxygen unites with ap 
to form CO,, the § is oxidized to H,SO,, the P to HjPO» ®" 
H to H,O. The first form in which the nitrogen — - 
