JTaxdary 7, 1898.] 



SCIENCE. 



19 



residual jelly in tbe bottle is dissolved by 

 shaking it with the water. When the jelly 

 has been thoroughly distributed through- 

 out the water the seeds to be inoculated 

 are sprinkled thoroughly and worked well 

 together so that a portion of the moisture 

 is attached to each seed. The seeds are 

 dried by mixing with some fine earth taken 

 from the field in which they are to be sown. 



The best method of applying nitragin is 

 to at first introduce it into a sufiicient 

 ■quantity of moist earth, which is subse- 

 quently thoroughly stirred from time to 

 time until the organisms have had time 

 to multiply and distribute themselves in 

 great numbers throughout the whole mass. 

 This moist mass, dry enough, however, to 

 permit of its being thoroughly stirred with- 

 out caking, is applied to the field either by 

 sowing broadcast or in ordinary drills such 

 as are employed in the distribution of fer- 

 tilizers. While, as has been said, the first 

 efiects have not been so good as have been 

 anticipated, there is suflBcient evidence to 

 warrant the belief that the use of nitragin 

 may in the near future become commer- 

 cially valuable. This leads to the hope 

 that we may find speedily verified the pre- 

 diction which I made some four or five 

 years ago to the effect that the nitrifying 

 organisms of the soil, in the form of reason- 

 ably pure cultures, would eventually be 

 used for fertilizing principles. The seeding 

 ■of the soil with appropriate nitrifying fer- 

 ments is certain to become as much of an 

 exact science as the use of the proper fer- 

 ments in butter and cheese making, in the 

 curing and fermentation of tobacco and 

 in other commercial operations where the 

 activity of bacteria conditions the character 

 and value of the product. 



Maze has recently shown that the life of 

 bacteria resident in the nodules of the Leg- 

 «minosse is not a pure symbiosis. It has 

 been demonstrated by this investigator that 

 where artificial conditions, suited to the 



nourishment of these bacteria, are provided, 

 they are able to oxidize free nitrogen in an 

 environment from which all plant life is 

 rigidly excluded. The bouillon in which 

 the bacteria were cultivated was obtained 

 from white beans. To this bouillon 2.5 

 per cent, of sugar and 1 per cent, of com- 

 mon salt and a trace of bicarbonate of soda 

 were added. The bouillon was solidified 

 by the addition of 15 per cent, of gelose 

 and was spread in layers 4 millimeters 

 thick on the botton of glass dishes about 20 

 centimeters in diameter. These vases were 

 so disposed as to be supplied with a current 

 of air from which every trace of oxidized 

 nitrogen was removed and which had been 

 subjected to a high temperature for a suffi- 

 cient length of time to entirely sterilize it. 

 This was accomplished by passing it through 

 a tube containing metallic copper heated to 

 low redness but not high enough to sen- 

 sibly diminish the content of oxygen in the 

 air. It was then conducted through a tube 

 filled with broken glass saturated with sul- 

 furic acid for the purpose of absorbing any 

 ammonia, next through a bottle containing 

 sterilized distilled water to saturate the air 

 with the vapor of water, whence it passed 

 to the dishes where the cultures were made. 

 In five days it was found that the sugar of 

 the broth was all consumed and that the 

 quantity of oxidized nitrogen in the bouil- 

 lon had been more than doubled. 



Thus it was proved that the bacteria of 

 the LeguminosEe, placed in a medium re- 

 sembling as nearly as possible that in which 

 they naturally live, are capable of oxidizing 

 free nitrogen without any symbiotic help of 

 any kind. If these deductions of Maze be 

 verified by subsequent investigators, it will 

 prove that the nodules in which these bac- 

 teria reside are only convenient places in 

 which they exercise their activitj^, which is 

 entirely independent of the vital activity of 

 the plant which they inhabit. 



The sources of the first organic nitrogen 



