Pure Cultures 227 



Pure cultures were secured in this manner by the 

 Dutch bacteriologist, Beyerinck, and by many others 

 after him. The Germans, Nobbe and Hiltner, conceived 

 the idea of preparing such cultures on a commercial 

 scale, and induced a manufacturing concern to place 

 them on the market under the name of nitragin in 1896. 

 Nitragin was a pure culture of the nodule-bacteria on 

 nutrient gelatin. It was sent out in flat, glass bottles, 

 stoppered at first with a cork, but later with a piece of 

 cotton. 



The persons purchasing such cultures were instructed 

 to dissolve the contents of the bottle in lukewarm water, 

 to moisten the seed with it, and, finally, to dry the latter 

 in a cool place and plant it. The large number of bacteria 

 contained on the gelatin were thus distributed among 

 the seeds and were carried by the latter into the soil. 

 Since each legume had, if not a different variety, at least 

 a different strain of the same variety best adapted to it, 

 the manufacturers supplied cultures for each legume. 



Nitragin. — The nitragin met with an enthusiastic 

 reception in Germany and elsewhere. It not only prom- 

 ised to supply bacteria to sojls lacking them, but, also, 

 bacteria of a high degree of efficiency. The rather 

 cumbersome method of inoculation with legume-earth 

 could be dispensed with, and the inoculation of soils 

 made safe and easy. The purchasers of nitragin were 

 many. It was tried by experiment stations and private 

 individuals in Europe and in North America and was 

 judged according to its merits. 



The results from its application in the first and second 

 seasons included some favorable reports, but they were 



