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able to assimilate by the help of the bacilli, so that the two are 

 mutually helpful, instead of the one being destructive to the other, 

 as in the case of ordinary parasites. In consequence of this pecu- 

 liar property of the leguminosi©, crops of this order of plants can. 

 be grown without any nitrogenous manures ; and, as I mentiooed 

 before, nitrogenous manures are very expensive. Experiments are 

 being made in the United States as to whether it is possible to get 

 the bacilli of a leguminous plant to live on the juices of one of the 

 grain-bearing plants such as wheat ; so that the latter might be 

 able to make use of the free atmospheric N. The plants selected 

 were the white melilot (Melilotus albe) closely similar to the 

 bokhara clover as the leguminous, and maize as the graminaceous 

 plant. The steps of the investigation have been to make a suitable 

 medium in which the bacilli of the melilot nodules would thrive ; to 

 gradually change this medium for a leguminous to a graminaceous 

 nature ; at the same time to modify the bacilli by successively 

 transferring them from a highly leguminous medium to a highly 

 and eventually an exclusively graminaceous medium, and finally to 

 inoculate graminaceous plants with the modified bacilli. The 

 leguminous plants eventually used were two. the white melilot and 

 the bean, au'i the graminaceous plants were maize and oats. A 

 considerable time must elapss before the investigation is completed, 

 but so far the indications are that the bacilli of leguminous plants 

 are capable of being sufficienily modified to develope to a certain 

 extent in the root cells of maize ; on the other hand, no visible 

 effect has yet been produced in the case of oats. Investigations of 

 this character cannot be unduly hurried, and much work has yet to 

 done in completing the details of the discoveries already made. It 

 is desirable to learn for example the exact ?-oIp of the bacilli and 

 what course of changes the free N. of the air undergoes in its migra- 

 tion into the plants. Questions such as these will no doubt be 

 answered in time, and the near future promises to be fruitful in the 

 solution of problems which must have a profound bearing upon the 

 development of economic agriculture. 



To recapitaiate briefly: Plants of the natural oi'der Leguminosfe 

 have little nodules in their roots. These nodules contain colonies 

 of bacilli. These bacilli live on the juices of the plant, and at the 

 same time have some effect on the N. of the air which exists in the 

 soil, so that the nodules contain an unduly large proportion of N. 

 This storage of N. is made use of by the plant in its developement. 

 Thus leguminous plants can obtain the N. they require for growth 

 in soils in which nitrates are deficient, so that otiier crops would 

 require costly nitrogenous manures. The roots of these leguminous 

 plants, being left in the soil, make the soil richly nitrogenous for 

 the next crop. A. problem now waiting solution is this — Can 

 wheat, oats, barley, and maize be supplied with a bacillus which 



