40 REPORT OF DEPARTMENT OF BACTERIOLOGY OF THE 
Inoculation by living. cultures placed upon the secd.— When it 
was found that the commercial cultures did not contain an appreci- 
able number of living Ps. radicicola it was decided to test the effi- 
ciency of the final steps in the proposed process of inoculation by 
treating alfalfa seed with living cultures of this germ. Accordingly 
the seed was treated with the culture, air-dried according to the di- 
rections furnished with the commercial culture and sown in plats 
beside similar plats of untreated seed. 
In order that there should be no question but that the seed was 
treated with an abundance of the desired germs it was all inocu- 
lated at the Station laboratory by M. J. Prucha, Assiscant Bacteri- 
ologist, with a pure culture of Ps. radicicola developed in a nitrogen- 
free medium according to the most approved methods. The culture 
which was used in most cases had been kindly furnished us by the 
U. S. Department of Agriculture as explained in Bulletin 270, page 
361. In other cases we used a pure culture which had been isolated 
from an alfalfa. nodule in our laboratory. 
Twenty-four farmers conducted tests of the efficiency of this 
method of inoculation in 1905. In order that seed from the same 
lot should be used on the inoculated and the uninoculated plats of 
each experiment each of the twenty-four farmers sent a portion 
of his seed to the Station for inoculation. There it was inoculated 
separately and returned by express as soon as thoroughly air- 
dried. The alfalfa seed inoculated in this way amounted to seven- 
teen and one-half bushels. e 
In most cases the test of inoculation upon the seed was conducted 
by the same farmers who were testing the effect of inoculation by 
means of soil and in such cases the check and two test plats were 
exposed to practically identical conditions except in the matter of 
inoculation. 
Of the 24 experiments with inoculated seed but 18 were so con- 
ducted and reported that the results can be relied upon. Twelve 
of these experiments were visited by a Station representative. 
The results of these eighteen tests of the effect of inoculation 
by means of pure cultures of Ps. radicicola placed upon the alfalfa 
seed are given in Table I. 
