GENESIS OF THE SOIL AND ITS POSSIBILITIES 185 



ganisms has been noted upon rocky particles from high 

 altitudes received in sterilized tubes, and where these 

 are sown in an. appropriate environment they soon pro- 

 duce colonies. The naked rocks of the Alps, the 

 Pyrenees, the Auvergnes and the Vosges, comprise min- 

 eralogical types of the most varied nature, viz., granite, 

 porphyry, gneiss, mica-schist, volcanic rocks and lime- 

 stones and all these have shown themselves to be 

 covered with the nitrifying ferment. It is known that 

 below a certain temperature these organisms are not 

 active; their action upon the rock is, therefore, limited 

 to the summer period. During the cold season their 

 life is suspended, but they do not perish, inasmuch as 

 they have been found living and ready to resume all 

 their activity after an indefinite sleep on the ice of the 

 glaciers where the temperature is never elevated above 

 zero. 



" The nitrifying ferment is exercised on a much 

 larger scale in the normal conditions of the lower levels 

 where the rock is covered with earth. This activity is 

 not limited to the mass of rock, but is continued upon the 

 fragments of the most diverse size scattered through 

 the soil and it helps to gradually reduce them to a 

 state of fine particles. The action of these fer- 

 ments is therefore a phenomenon of the widest exten- 

 sion. 



" The action of these microorganisms, according to 

 Miintz, is not confined to the surface, but extends to 

 the most interior particles of the rocky mass. Where, 

 however, there is nothing of a nitrogenous nature to 

 nitrify such an organism must live in a state of sus- 

 pended animation unless it is able to act on the nitrogen 

 of the air. 



" When the extreme minuteness of these phenomena 



