115 



investif^jation of Winofjradsky, tliese ferinonts are able to assimilate 

 aiimioniiuii carbonate, lonii orj;auic matter from it, and at the same 

 time change part of the nitro<?en of the ammonia into nitric acid. The 

 author also believes that they may utilize for their sustenance the very 

 minute traces of alcohol which he has found to be widely distributed 

 and a constant constituent of tlie atmosphere. All the conditions 

 for their growth would therefore be fullilled on bare rock and on the 

 hi{?hest mountain peaks. Being of microscopic size they are able to 

 l)enetrate the ca])illary interstices of rock and the nitric acid which 

 they produce, acting constantly through long periods of time, becomes 

 an effective means of disintegration. 



The disintegrated particles are found on examination to be uniforndy 

 covered by layers of organic matter, evidently formed by these organ- 

 isms. This accords with the observation of Winogradsky, that the 

 nitrobacteria grown in liquids free from organic matter gather about 

 deposits of carbonates and transform ammonia and carbonic acid into 

 organic matter, which thus accumlates in considerables quantities.* 

 The accumulation of the organic matter of the soil thus begun is 

 increased later by the residues of the vegetation of higher orders. By 

 putting specimens of disintegrating rock into sterilized tubes and mak- 

 ing bacteria cultures with them, the author showed the presence of 

 nitrifying organisms in the bare rocks of the Alps, Pyrenees, Auvergne, 

 and Vosges. Kocks of the most widely varying mineralogieal character 

 — granite, porphyry, gneiss, mica schist, volcanic rock, limestone, and 

 sandstone — were thus shown to be covered with nitro bacteria. Schlo- 

 sing and Miintz have shown that these organisms become dormant at low 

 temperature, so that their activity is limited to the summer, especially 

 at high altitudes, but their life does not cease in winter, for he has found 

 them "living and ready to resume their activity after a sleep of ages 

 under the enduring ice of glaciers, where the temperature does not rise 

 above zero." 



But while the organisms are so abundant on the bare rocks of higli 

 mountains where the conditions for their action are most simple, their 

 nitrifying activity is exercised on a far vaster scale under the normal 

 conditions existing at lower levels, where the rock is covered with vege- 

 table soil. They act ui)on minute fragments, and thus reduce them to 

 smaller and smaller size; nor are they limited to the surface, but tliey 

 penetrate into the Interior of the rock mass. This is the case with the 

 rock material known as "rotten rock," the particles of which become sep- 

 arated, as often happens in limestone, schists, and granite. " In such 

 decomposing rocks," says the author, " 1 have always established the 

 l)resence of the nitrifying organism." One of the most striking examples 

 of this is furnished by the mountain in Switzerlan<l called in German 

 Faulhorn, in French Pic Pourri (" Potten Peak"), which consists of a 



• See Experiment Station Record, vol. ii, p. 754. 

 5G0'8— No. 2 4 



