BACTERIA AS FERTILIZERS. 59 



time the product was put upon the market under the name of 

 " Nitragin " and sold at the rate of one dollar per bottle, which 

 was sufficient for one-half acre. Numerous experiments abroad, 

 with a few in this country, soon demonstrated that while in some 

 instances Nitragin produced an abundant formation of nodules, 

 there was a vastly greater number of cases where no benefit 

 was obtained. 



When this line of investigation was taken up in the Depart- 

 ment of Agriculture, the demand for some artificial means of 

 inoculating soil was already sufficiently great to make it desirable, 

 if possible, to increase the bacteria very rapidly and to insure a 

 sufficient quantity of them so that they could be distributed to 

 various parts of the country where it seemed that they were 

 needed. For this reason the means used for propagating them 

 was similar to that of the German botanist ; that is, clover or 

 bean, or whatever the plants from w^hich the bacteria originally 

 came, was stewed and to this decoction were added sugar, pep- 

 tone and other substances ordinarily used in cultivating bacteria. 

 The result was a medium very rich in nitrogen and the growth 

 obtained was all that could be desired. 



At this stage the problem seemed an exceedingly simple one 

 and it was thought that within a short time it would be possible 

 to send out bacteria by the keg, barrel, or any quantity desired. 

 Unfortunately, however, when these organisms were tested in 

 the greenhouse and in the field, it was found that they did not 

 produce nodules. There could be no question about their having 

 been derived from the true nodule-forming organism, but it 

 looked as though they had by some means or other lost the 

 power of infecting the plants upon which it was so desirable to 

 have them produce root nodules. After a little experimenting, 

 it became evident that the manner of growing these bacteria was 

 not one designed to make them efficient nitrogen fixers. When 

 you remember that these organisms reproduce themselves in from 

 thirty to forty-five minutes, you can readily see that if they are 

 at all susceptible to their environment, the tremendous number of 

 generations obtained at the end of a few days enables any slight 

 difference in their efficiency to be transmitted in a most astonish- 

 ing way; and that, although one started with an organism 



