LUTHER BURBANK 



has experimented with a method of distributing 

 liquid cultures in glass tubes. Special packages of 

 minerals, including phosphate of potassium, sul- 

 phate of magnesium, and ammonium 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 

 agriculture that would have been quite incompr< 

 hensible to any one 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 vital activi- 

 ties of animals and plants that the sprinkling o\ 

 the soil with bacteria seems almost as common- 

 place a performance as the sowing of seed. 



This method, however, is obviously only ai 

 accessory to the methods of the plant developer. 



It has exceptional interest as illustrating th< 

 application of science to the art of agriculture, 

 but it has no direct association with the work of 

 the experimenter who develops plants by hybridiz- 

 ing and selection. 



[102] 



