114 



left intact. When sterilized at 120° C, it was found that generally no 

 ammonia was formed, thus implying that the ammonifying ferment is 

 destroyed. But when soils thus sterilized were inoculated with a par- 

 ticle of fresh soil, the production of ammonia recommenced. 



The principal results of the experiment may be recapitulated by say- 

 ing that in soils in which nitrification could not occur or in which the 

 nitric ferment had been killed, the nitrogen of organic substances was 

 changed to ammonia exclusively. Soils poorly adapted to nitrification 

 had nearly all their nitrogen, changed into ammonia and but little to 

 nitric acid; and in arable soils where nitrification was very intense 

 ammonia was not entirely absent. 



The author concludes that in all soils special organisms exist which 

 exercise the function of converting the nitrogen of organic matter into 

 ammonia. But there are almost always coexisting organisms which 

 transform the ammonia thus produced into nitric acid. Although the 

 work of the former is only preparatory, yet it is useful and perhaps 

 even indispensable. 



In another article [Compt. rend., Ill (1890), j). 75) P. Pdchard calls 

 attention to his own results which are identical with those of Miintz 

 above referred to, but were published earlier in the account of an 

 investigation on the inlluence of gypsum and of clay on the retention, 

 nitrification, and fixation of nitrogen (Compt. rend., 109 (1880), j). 04G). 

 lie there showed that in the decomposition of organic matter the forma- 

 tion of ammonia i)recedes that of nitric acid. This conclusion, he says, 

 was to be expected after the work of Shiitzenberger on the decomi)osi- 

 tion of albuminoid substances by the earthy alkalis, especially wjieu 

 Duclaux had shown that their decomposition in the manner named 

 is similar lo that produced by the action of microbes. — [W. O. A.] 



The decomposition of rocks and the formation of arable soil, 

 A. Miintz (Compt. rend, 11(» (1>^1»0), [>. i;;7(»).— In this article tiie author 

 broaches the very striking theory that either nitrobacteria or similar 

 microscopic organisms constitute one of the principal agencies in the 

 decomposition of rock and formation of soil, and supports it by a variety 

 of observations. Both igneous and sedimentary rocks undergo constant 

 disintegration. The fine particles either left in situ or transported by 

 wind and water during geologic epochs, make the basis of arable soil. 

 The disintegration is caused in part by atmospheric agencies, chemical 

 and physical, and in part by the action of living organisms. It is well 

 known that plants of the higher and lower orders growing on the sur- 

 faces or in the fissures of rocks, tend to disintegrate them by the action 

 of acid or other secretions, as well as by mechanical moans. According 

 to the observations of the author, microscopic organisms exert a similar 

 but more subtle and far more general action. He has studied the action 

 of these nitrifying ferments upon high mountains, above the limits of 

 ordinary vegetation, as well as in lower regions. As first indicated by 

 the researches of Schlosing and Miintz and explained later by the 



