•'»''♦- Bulletin 167 



which were studied, attention is directed to a few clauses ab- 

 stracted from Fliigge's description of his Bacillus fluorescens 

 liquefaciens (6:11: 292). "The degree of liquefaction varied 

 very considerably. There were varieties which in 2 days and 

 others which first in 2 weeks liquefied the gelatin ; the form of 

 the colonies varied, also, from spherical to spreading with bor- 

 der entire to toothed. The optimum temperature was 20 to 

 25 ° C. Many varieties do not grow at 37 ° C, others grow well 

 and form on agar a more or less thick layer. The oxygen re- 

 quirements are equally variable ; through them are explained the 

 different forms of liquefaction in stab cultures. If one wishes 

 to conceive all minor variations as constant characters, one must 

 make dozens of varieties." 



According to Fliigge (1. c.) Bad. bittyri fluorescens La- 

 far, B. fluorescens nivalis Schmelck, Bacillus viscosus Frank- 

 land and B. fluorescens minutissinius I una may be regarded as 

 synonymous with B. fluorescens liquefaciens. In the description 

 of B. fluorescens non-liquefaciens, he says. "A sharp line between 

 the liquefaciens and non-liquefaciens variety of B. fluorescens 

 does not exist since there are forms which in the first day of plate 

 growth appear to belong to the latter group, which later sink 

 gradually in the gelatin." 



It is believed that the morphological, cultural, physical and 

 biochemical features of the 13 strains of green fluorescent bac- 

 teria warrant the assumption that there are but two species rep- 

 resented : Pseudonwnas fluorescens and an unknown species, 

 strain CXV, which, as has been previously noted (c. f. page 546), 

 never evidenced more than doubtful fluorescence. 



Ps. fluorescens is represented by 12 strains which are di- 

 visible into two varieties, liquefaciens and non-liquefaciens. The 

 following strains belong to the liquefaciens variety: fluorescens 

 inescntcrica, CXII, CXLV, CXLVIII, XXXVI and LI. To the 

 non-liquefaciens variety belong, alba, longa, putrida and, pro- 

 visionally, tenuis and strain CXL, which showed a very tardy 



