BIOLOGY OF SOILS 151 



The crop from the uninoculated plot must be reckoned 

 a fair one. The plants were healthy, and the roots were 

 covered with nodules. All the inoculated plots have given 

 a larger yield. With Hiltner's preparation the increase 

 is distinct and substantial. In the other two plots the 

 increase is so small as to come within the ordinary varia- 

 tions in experiments of this kind, and cannot be confidently 

 attributed to the inoculation. Even in the case of Hiltner's 

 preparation, it should be remembered that the experiment 

 has lasted only two years. The results must be confirmed 

 before it can be assumed that similar benefits will gene- 

 rally follow such treatment. 



Fixation by Non-leguminous Plants. It is still uncer- 

 tain whether plants belonging to orders other than the 

 leguminosse can assimilate nitrogen in its elementary form. 

 Certain experiments seem to show that such is the case, 

 but they are not considered entirely conclusive. There 

 is, at least, no satisfactory evidence to show that any of 

 them possess this property in anything like the same degree 

 as the leguminous plants. On the other hand, there is 

 much negative evidence to the contrary. 



Alinite. The name alinite has been given to another 

 bacterial preparation for supplying nitrogen to crops. It 

 is not now believed that the organisms in this kind of 

 culture have any power of fixing the free nitrogen, but they 

 probably accelerate the decomposition of nitrogenous 

 organic compounds. It has been found to give positive 

 results on soils rich in humus. 



DESTRUCTION OF ORGANIC MATTER. 



Decay and Putrefaction. When organic matter is 

 burned it undergoes oxidation, and the elements of which 

 it is composed except nitrogen are liberated as oxides. 

 It is also destroyed when heated in the absence of oxygen ; 



