FOOD FOR LIVE STOCK 43 



is necessary, however, to treat the solution in a 

 particular way in order to insure that the micro- 

 organisms may maintain vitality. If they are 

 dried slowly under the usual atmospheric condi- 

 tions, the microbes die. 



It has been found possible to preserve them by 

 rapid drying of pieces of cotton dipped in a solu- 

 tion containing the microbes e 



The Department of Agriculture at Washing- 

 ton has experimented with a method of distrib- 

 uting liquid cultures in glass tubes. Special 

 packages of minerals, including phosphate of 

 potassium, sulphate of magnesium, and ammo- 

 nium phosphate, are sent with the culture tube 

 to make a nutrient medium in which the culture 

 may be developed. 



The clover seeds are moistened with this liquid 

 culture, dried rapidly, and sown as quickly as 

 practicable. 



Another method is to sprinkle the liquid on a 

 portion of soil and scatter this over the land. 



This inoculation of the soil with the nitrogen- 

 fixing microbes constitutes a new departure in 

 agriculture that would have been quite incom- 

 prehensible to anyone before the day of the 

 modern bacteriologist. But so much has been 

 learned in recent years about the bacteria and 

 their almost universal prevalence and share in the 



