1 1 2 THE NEW AGRICULTURE. 



They did it, and the cultures now to be had have such nitrogen 

 fixing power and such hardihood that they are from three 

 to eight times as efficient as their progenitors, and they may 

 be transported to any distance and left in a dry and inactive 

 state for almost any length of time. 



In the preparation of these bacteria for agricultural use 

 the interior of a root tubercle is cut out and mixed with a 

 medium of water containing I per cent, of commercial agar- 

 agar, about I per cent, of sugar, from .02 to .05 per cent, of 

 magnesium sulphate, and approximately .01 per cent, of po- 

 tassium phosphate. Pure cultures being obtained, they are 

 then transferred to a "second medium made of the same material 

 as the first, one cubic centimeter (a drop) of the culture being 

 sufficient to impregnate 100 liters (100 quarts of fertilizing 

 fluid). In this solution, which must be kept in a warm place, 

 the organisms increase very rapidly, though their food supply 

 is furnished wholly from the pure nitrogen of the atmosphere. 

 Large quantities of this culture solution will within a few 

 days become milky in appearance, due to the presence of the 

 immense number of the developed bacteria. For the inocula- 

 tion of the soil the fluid is then sprinkled either over the sur- 

 face of the area to be fertilized or upon the seed to be planted 

 in it, but for distribution absorbent cotton or other suitable 

 material is dipped into the fluid containing the organisms and 

 thoroughly dried, etc., in a chamber free from dust or other 

 forms of contamination. It is in this form that the organ- 

 isms may be kept indefinitely, and safely and cheaply trans- 

 ported by mail or otherwise to any part of the country. 



The planter, upon receiving one of these packages of im- 

 pregnated cotton, simply soaks it out in a suitable vessel, and 

 within a few hours he may have as many gallons of bacteria- 



