2G Prof. M. C. Potter. Bacteria as [Jan. 18, 
The determination, by measurement with the thermopile, of the rise of 
temperature due to oxidation becomes a very valuable confirmatory experi- 
ment in conjunction with the method of testing the evolution of CO2 by 
titration. 
It has been conclusively established by means of the thermopile that a 
definite rise of temperature occurs when carbonaceous substances such as 
charcoal, coal, peat, etc., are subject to the action of certain bacteria. And 
in this connection it must be remembered that the rise of temperature is 
maintained for some considerable time, and that the double-walled vacuum- 
flask, with at least a portion of the wires composing the thermopile, are 
steadily preserved at this temperature above the surrounding medium, in 
spite of any loss from radiation. There must thus be a continuous dissipation 
of heat and the amount generated is therefore more than actually appears; it 
must also be taken into consideration that this rate only applies to 
conditions 7 vitro and in a laboratory. Probably, in the soul, the carbon 
would be attacked by micro-organisms under circumstances more favourable 
to their activity and the oxidation would proceed much more rapidly. It is 
of importance to recognise that every process of oxidation raises the 
temperature in an appreciable degree, and this is a factor which should be 
taken into account in all problems relating to the soil. 
Indeed, the action of bacteria in promoting exothermal changes is a subject 
too generally neglected. It must now be recognised as possessing a practical 
bearing upon investigations connected with oxidation of coal. The suggestion 
may also be made that in some cases of spontaneous combustion of coal, the heat 
generated by microbial activity is an influence to be taken into consideration, 
and may be a dangerous motive force acting upon explosive gases. 
That carbon should be proved to undergo oxidation by bacteria is not 
surprising when we consider the fact that nitrogen undergoes the same 
process, while the oxidation of sulphur by bacteria has been established by 
Beijerinck (1) and quite recently that of hydrogen by Kaserer(4). The 
author has previously shown that oxalic acid undergoes decomposition into 
COQ2 and H20 by the agency of a soil bacterium (6), a result which has since 
been confirmed independently by Hall (3). 
Incidentally the present investigation throws some lght upon the 
formation and «decomposition of coal. In the ordinary course of events 
vegetable matter gradually undergoes a process of decay, countless bacteria 
and fungi deriving their sustenance from it and gradually effecting the 
dissolution of the cellulose and other compounds, until, ultimately, the end- 
products are reached. This process demands, among other things, a constant 
supply of oxygen, and in the absence of this element only a partial reduction 
