1905] TRANSEAUBOGS OF THE HURON RIVER VALLEY 369 



of ammonia. This is at once attacked by the nitrifying bacteria, 

 and changed successively to the form of a nitrite and a nitrate. The 

 two latter changes again involve the addition of oxygen. 



If we consider only the temperatures occurring in nature, we may 

 say that these activities increase regularly with the temperature. As 

 to water conditions, it has been shown that in air-dry soil eremacausis 

 is practically wanting, and that when the soil is filled with water it is 

 reduced to a minimum. Between these two extremes lies an optimum 

 at which there is sufficient moisture for the life of the organisms, and 

 yet not enough to interfere with the diffusion of oxygen. An acid 

 condition impedes, and a slight alkalinity favors, the production of 

 both the carbon and the nitrogen compounds. 



Eremacausis is then essentially a process, of oxidation, brought 

 about by lower organisms, whose activities are favored by a high 

 temperature, a slightly alkaline medium, and free access to the air. 

 Its products are simple compounds which may furnish food materials 

 for the higher plants living on the substratum in which they are formed. 



By putrefaction is meant that process of disintegration which 

 occurs when organic matter decays in the absence of oxygen. Here 

 again organisms are involved, but they belong for the most part to 

 the anaerobes, and are wholly forms of bacteria. The process is 

 essentially one of reduction. 



Carbon dioxid is again the principal gaseous product", but its 

 relative amount is greatly reduced. Along with it CH 4 , H, H 2 S, 

 H 3 P, N 2 O, and N are produced in small quantities. In the manu- 

 facture of the carbon dioxid the oxygen is not only derived from the 

 organic matter, but also from nitrous oxid, nitrites and nitrates which 

 may be present. In the decomposition of cellulose, carbon dioxid 

 and methane result from the hydrolysis of the cellulose molecule. 

 Albumins at first break up into amido-acids, nitrogenous compounds 

 of the aromatic series, and other little-known bodies. If the decom- 

 position continues, the amido-acids in turn form ammonia and 

 compounds of the fatty-acid series. The latter substances may 

 still further disintegrate to carbon dioxid, hydrogen, and methane. 

 Depending upon the stage in the progress of decomposition, we may 

 find complex organic compounds, organic acids, and their salts, or 

 comparatively simple substances. 



