IMPROVEMENT OF THE SOIL 66 



The infected seed is planted and quickly covered 

 while still moist. Various methods have been devised 

 for safely transporting and distributing pure cultures 

 of these useful organisms, but none of them have as 

 yet proved fully satisfactory in practice. The one 

 adopted by the United States Department of Agri- 

 culture and most in use at the present time consists 

 in saturating portions of absorbent cotton with fresh 

 cultures of the bacteria and then quickly drying 

 them. If the dried cotton is now securely wrapped 

 to prevent it from again absorbing moisture, the 

 culture will retain its vitality for a considerable 

 period of time, and the packets of dried cultures may 

 be safely shipped through the mails. If, however, 

 the culture is exposed to alternate moisture and 

 dryness, it soon dies. For use the bits of cotton 

 with the dried culture are dropped into a bucket of 

 water containing a prescribed portion of nutrient 

 salts. In a few hours the liquid becomes turbid 

 from the growth of the organisms, and it is now 

 ready for moistening the seed. These dried cultures 

 can be obtained commercially from most of the 

 larger seedsmen, and while their use is often attended 

 with failure, it is well worth making repeated efforts 

 to get this and the next-mentioned crop established 

 in new localities. The effect of a successful inocula- 

 tion is sometimes little short of miraculous, the 

 plants growing with the greatest vigor and producing 

 a crop at the rate of one and a half or two tons of 

 hay per acre, while on adjoining uninoculated plots 

 the plants soon turn yellow and stop growing when 

 only a few inches high. Such an experiment has to 



