54 Report OF THE BACTERIOLOGIST OF THE 
into the water containing the organisms or the water containing 
the organisms is sprinkled upon the cotton or other material and 
the same thoroughly air-dried in a chamber free from dust or 
contamination by molds. The drying is facilitated by forcing a 
current of air through the chamber by aspiration through sul- 
furic acid, potassium hydroxid, calcium hydroxid, sodium 
hydroxid, or any of the other ordinary materials used in labora- 
tories for drying. In this_dry form the organisms may be kept 
indefinitely without deterioration or change and may be safely, 
easily, and cheaply transported to any distance, either through 
the mails or otherwise. In using the organisms preserved as 
above described the dry absorbent material containing them is 
simply dropped into a water solution of the same composition 
as above described. Where the purpose is to treat soil or seed, 
it is not necessary to observe strictly antiseptic precautions. 
Ordinary clean vessels or tubs may be used, simply protected 
from dust, and ordinary wellwater or rainwater is used in making 
the culture solution, as the amount of ‘nitrates or ammonia 
which such waters ordinarily contain does not interfere with the 
vitality of the organisms at this stage of the process. The tem- 
perature and light conditions should be as previously stated. In 
from twelve to forty-eight’ hours the organisms will have in- 
creased in the water culture as in the first instance. At this 
stage in order to stimulate a very rapid division of the bacteria 
about one per cent. phosphate of ammonia is added to the culture 
solution. The quantity of liquid culture that may thus be ob- 
tained is limited only by the amount of water used containing the 
sugar, magnesium sulfate, and potassium phosphate or other 
equivalent sources of magnesium, potassium, and phosphorus, as 
above described. After thus obtaining the liquid culture it is 
then necessary only to sprinkle the seeds or soil to be treated 
with water containing the organisms or to dip the seeds into 
water containing the organisms and then dry them in the ordinary 
way to facilitate planting. The propagation of the bacteria 
should not be continued longer than twelve to forty-eight hours 
after the addition of the phosphate of ammonia; otherwise they 
will deteriorate in nitrogen-fixing power, as previously explained, 
and organisms thus stimulated should be used only for seed or 
soil impregnation and not for preservation or distribution. 
