2.^2 



of Stoklasa and Ernst^ who reckoned the respiratory intensity from lOO g. of 

 dry substance of the Bacterium Hartlebi, a denitrifying bacterium, to be 2.5 

 g. of carbon dioxid per hour; in the same amount of dry substance of Clost- 

 ridium gelatinosum, an ammonia former, the culture gave 2.t) g. carbon 

 dioxid. The fact that the carbon dioxid production of a field is actually de- 

 pendent primarily, on bacterial life, is demonstrated by the circumstance that 

 no carbon dioxid was produced in observable quantities after experimental 

 earth had been sterilized. 



We find the following statements in the work of the above named 

 authors on the influence of aeration. Forest soil taken from a deep position 

 gave 59 mg. per kilo, of carbon dioxid within 24 hours in aerobiosis o mg. 

 in anaerobiosis, while peat soil yielded 41 mg. in aerobiosis and 7 mg. in 

 anaerobiosis. Naturally, heat and moisture also act determinatively. The 

 greater the production of carbon dioxid' in a field, the more completely does 

 the chemical process of the combination of the free ammonia take place, as 

 Schneidewind- has observed. This question comes under consideration here 

 in as much as the losses in nitrogen with an addition of animal manure rep- 

 resent an impoverishment of the stores in the soil. If stable manure with 

 ordinary treatment is left in a manure pit, it shows a nitrogen loss of 30.31 

 per cent, after lying three months. If it lies, however, on an underlayer of 

 old manure, producing a great deal of carbon dioxid, the loss amounts only 

 to 16.94 per cent. Here the abundant carbon dioxid must have combined the 

 free ammonia or have prevented the disassociation of the ammonium carbo- 

 nate already formed. 



Among the most serious injuries, because the most frequent, be- 

 longs the so-called "unripe soil." This is distinguished by its lack 

 of elasticity from the ripe soil which, under the influence of the soluble 

 salts in the soil and the micro-organisms, takes on the friable structure al- 

 ready described. In consideration of the great work which the bacteria per- 

 form in soil decomposition, we can assert that the ripeness of the soil is due 

 to their work. If we do not know by far all the processes taking place in 

 ripening soil, we do know that we may consider the ripening up to a certain 

 stage as actual fermentation. Attention need be called here only to the special 

 pectin fermenting organisms (Plectridia) which seem of importance in germ- 

 inating seeds of the Leguminoseae and further to the cellulose fermenting 

 organisms with the great formation of hydrogen and methane (marsh gas 

 CH4). Further, the Streptothrix species come under consideration as humus 

 fermenting organisms, but especially the granulose organisms forming acids '', 

 which produce chiefly butyric acid and carbon dioxid. In this, the Plectri- 

 dia take over the chief share in the mineralization of the organic substances. 



1 Stoklasa, J., and Ernst, A., Ueber den Ursprung, die Menge und die Bedeutung 

 des Kohlendioxyds im Boden. Centralbl., fiir Bakteriologie etc. Section II, 1905, Vol. 

 XIV. Nos. 22 and 23, p. 725. 



2 Schneidewind, Zur Frage der Stalldiingerkonservierung. Deutsche landw. 

 Presse 1904, No. 73. 



3 Lohnis, P., Ueber die Zersetzung des Kalkstickstoffs. Centralbl. f. Bakt. II, 1905, 

 No. 3-4, p. 87, 



