206 Kansas Academy of Science. 



in acid soils, nor in soils strongly alkaline, but do best in soils 

 faintly alkaline. Acid soils must be neutralized by alkaline earths, 

 such as quicklime and wood ashes ; alkali spots should be sanded 

 and drained, or crude sulfuric and nitric acids may be sprinkled 

 over such places. 



The air-loving, nitrifying bacteria work on the surface of sewage 

 in the retention vats, and very vigorously when it has been passed 

 out into small, open fields, where the sewage may stand a few days, 

 spread out in a stream a few inches thick. The bacteria reduce 

 organic matter unreduced and oxidize the ammonia, nitrites, and 

 sulfites. When this work has been completed, the sewage is ready 

 to be used as a fertilizer. 



The nitrifying bacteria use various organic matters (of which 

 phosphates are essential constituents) as foods, though the remark- 

 able fact has been discovered that the nitrifying organisms can de- 

 velop and perform all their functions on inorganic materials. They 

 have the power to live and grow in a medium consisting solely of 

 acid carbonates of sodium and calcium in an ammoniacal solution 

 undergoing nitrification. No other plants destitute of chlorophyll 

 can do this. 



The nitrous bacteria have been named Nitrosomonas and Nitro- 

 sococcus, and the nitric organism the Nitrohacter. These are evi- 

 dently most valuable to all farm crops, as without them the soil 

 would soon become barren. 



4. The root-tubercle bacteria are recent discoveries. For a long 

 time it has been known that the clovers, peas, beans and other le- 

 gumes not only do not exhaust the soil, but even leave it in better 

 condition than before the crop was grown. Certain tubercles on 

 the roots of these plants are crowded with bacteria which are now 

 known to possess the power to use the free nitrogen and oxygen of 

 the air in preparing those compounds of nitrpgen that serve as 

 crude food materials to the host-plants. The mutual relation ex- 

 isting between the legume and the bacteria is not well understood, 

 but there is no question as to the benefit accruing to the host. 



Certain companies are now preparing cultures of bacteria, appro- 

 priate for use on the several crops of legumes, to sell to farmers 

 and gardeners. The Western Nitrogen Culture Company, of To- 

 peka, prepares packets of bacteria and food, to be used on sixteen 

 important legumes, one packet for each kind. The tubercle bac- 

 teria do not thrive in acid or strongly alkaline soils, but in average 

 Kansas soil they multiply rapidly, and their excretions in the 

 tubercles cause a greatly increased growth of the legume and at 



