RECLAIMING LOST NITROGEN. 149 



appeared that not all species of legumes are capable of devel- 

 oping root tubercles equally well in all soils. Some soils will 

 luxuriantly support certain species of beans, peas or clovers, 

 producing a large crop, developing quantities of tubercles and 

 fixing an abundance of nitrogen, while the same soil will not 

 support other species of legumes with equal readiness. For 

 example : the soil of Connecticut is not adapted to the legume 

 called the soy bean. When this bean is planted in the ordi- 

 nary Connecticut soil it does not flourish but yields a small 

 crop, unless heavily fertilized, and does not produce tubercles. 

 This species does, however, grow readily in Massachusetts. 

 Some years ago the experiment was tried of importing the 

 Massachusetts soil, upon which this plant had produced abun- 

 dant tubercles, and mixing it with the Connecticut soil, subse- 

 quently planting the soy bean. The result was an excellent 

 growth of the soy bean and the development of tubercles in 

 the Connecticut soil. At the present time these particular 

 plots of land are capable of producing large luxuriant crops of 

 the soy bean, with abundant root tubercles and a large fixation 

 of atmospheric nitrogen. It is interesting to note that the same 

 experiment has been repeated in Germany, where the soy bean 

 does not readily grow. In this case soil was imported from 

 Japan, where the plant flourishes, and was used for supplying 

 the German soil with the proper species of organism. The result 

 was equally successful with those of Connecticut experiments. 

 Kvidently Connecticut soil does not contain the species of bac- 

 teria adapted for producing the tubercles in the soy bean, al- 

 though those which produce tubercles on the pea and the 

 clover are abundant enough. 



These experiments indicate that the root-tubercle bacteria 

 are not all alike, and that some species of legumes are not cap- 

 able of flourishing and developing tubercles under the influ- 

 ence of the same kinds of bacteria which produce the tubercles 

 in other species. 



