76 REPORT OF THE BACTERIOLOGIST OF THE 
faint growth after six days. The cotton is, however, probably 
sterile so far as Ps. radicicola is concerned, as the latter germ 
grows readily in medium 48, and would likely have developed 
sooner had it been present. 
“Wax bean No. 32.—Turbidity moderate on third day. Micro- 
scope shows long, actively motile rods of B. subtilis Group. None 
of the Ps, radicicola type. Plates showed colonies of B. rwminatus, 
none of Ps. radicicola. Conclusion: Contains no living Ps. 
radicicola and only spores? of two common members of the B. 
subtilis group. 
“Wax bean No. 33.—Moderate turbidity on the third day. 
Plates on 48 agar showed colonies of a small polymorphic bacil- 
lus which stained brown with iodine—Ps. radicicola? Plates on 
plain agar showed colonies of B. asterosporus, and a small poly- 
morphic bacillus. Conclusion: Cotton probably contains a few 
living Ps. radicicola. 
“The cultures from cotton included in the preceding tests were 
made from media prepared from distilled water. 
“The failure to obtain a growth of Ps. radicicola, in most cases, 
was, I believe, not due to any deficiency on the part of the 
medium. Cultures of alfalfa and crimson clover bacteria, dried 
on cotton gauze, very recently prepared in this laboratory from 
pure cultures, were inoculated into.a portion of the medium used 
in the preceding tests. There was in each case an abundant 
growth, especially after the addition of the ammonium phos- 
phate, and plates made with 48 agar gave typical Ps. radicicola 
colonies. 
“In fact I have been able to grow Ps. radicicola, although the 
growth is more feeble, in media made from ammonia-free distilled 
water. 
“From this it is reasonable to assume that had Ps. radicicola 
been present on the specimens of cotton it would have developed 
in the cultures made therefrom. . 
“In the previous notes I have spoken of the cotton as sterile 
or as containing no living Ps. radicieola. This statement has 
only a relative significance. The organism may be entirely dead, 
or it may have only have had its viability so reduced that it 
fails to develop in the culture medium, singly or along with other ~ 
