304 CHARLES B. LIPMAN 



the dry weight of the soil we find the latter salt concentration 

 alone depresses the nitrifying power of the normal soil by about 

 75%. When, however, we add to it varying quantities of NaCl 

 ranging from 0,05% up to 0.2% inclusive, nitrification is not 

 only very much improved but at the last concentration men- 

 tioned is superior to that of the normal salt. Yet one of the 

 salts alone depresses nitrification by about 75% and the other 

 alone by about 50%. 



Still more amazing than the data of Table VIa are those of 

 its reciprocal Table VIb. Indeed the latter presents in many 

 respects the most striking data in all the experiments described 

 herein. Thus 0.2% NaCl alone depresses the normal nitri- 

 fying power of the soil by considerably more than 50%, and 

 0.05% Na2C03 alone depresses it by about 75%. Yet when the 

 two are added to the soil together the nitrifying power is increased 

 by more than 25% above that of the normal. Even greater 

 stimulations are obtained when smaller quantities of Na2C03 

 are added to the 0.2% NaCl. The fact, however, which is most 

 striking in this last table is that amounts of Na2C03 two or three 

 times as large as that which alone depresses nitrification by 

 about 75% can be made absolutely innocuous, and even allow of 

 a stimulating effect on nitrification, if 0.2% NaCl is added to 

 them. 



SUMMARY AND CONCLUSIONS 



The data above submitted dealing with the antagonism be- 

 tween anions as related to the production of ammonia and 

 nitrates in soils through biological agencies forms the most strik- 

 ing evidence thus far adduced in investigations of this kind. In- 

 deed, more narrowly considered, it represents to date only the 

 third set of experiments which testify to the genuineness of an- 

 tagonism between anions, and it sets forth the evidence in hand 

 in support of the principle under discussion in a much more 

 striking and convincing manner than the others mentioned. 



These results therefore testify 1st to the general nature of 

 Loeb's conception of physiologically balanced solutions, 2nd 

 to the relatively new or obscure fact that anions are as effective 



