562 Bulletin 167 



the olive green color noted with the latter organism. No other 

 points of difference were observed. 



Si rain XXXVI. — This strain could not be distinguished from 

 Ps. fluorescent or strain CXLVIII, except by a more feeble fluo- 

 rescence on alkaline gelatin. 



Strain LI. — This organism also resembled Ps. fluorescens 

 closely. It could be distinguished only by the fact that liquefac- 

 tion was delayed, first appearing in about 50 days. LI is evi- 

 dently a strain of Ps. fluoresceins, tending toward the variety iion- 

 liqucfaciens. 



The non-liquefying type. — To this group belong the follow- 

 ing organisms: Ps. putrida, Ps. alba, Ps. longa. Strains Ps. 

 tenuis and CXL are classified here provisionally since liquefaction 

 is long delayed. Cultures were held under observation for six 

 months in a moist chamber at 18 to 20 C. 



Ps. putrida. — Growth was slow, becoming visible the fourth 

 day ; the stab was filiform above and beaded below with a small 

 white colony at the surface. At 12 days the colony was round 

 and brownish, the surface being' somewhat contoured. At 20 

 days the colony had become chocolate brown at the center, and 

 the edge showed spiny outgrowths. In from 20 to 40 days the 

 medium showed a strong browning, beginning at the surface and 

 progressing slowly downward. No liquefaction was observed in 

 five months. At this time the colony was round, about 1 cm. in 

 diameter, having a reddish-brown center and raised edge with 

 rhizoid and spiny processes; the puncture was beaded and villous. 



Ps. alba and Ps. longa. — Cultures were similar to those of 

 Ps. putrida, but no browning of the colony or of the medium 

 was apparent. In 5 months the following characters were in 

 evidence; colony, white, round with beaded to lacerate edge: 

 puncture, beaded and widely villous in the upper portions; no 

 liquefaction. 



Ps. tenuis. — Young cultures were not essentially different 

 from those of Ps. alba and Ps. putrida. Some colonies were 

 round and entire, while others were erose. The stab was filiform 



