288 IMPORTANT VARIETIES OF FISSION-FUNGI. 



Microscopic Appearance. Small, slender rods, often 

 growing into exceedingly long threads. Thickness, 0.4- 

 0.8 A*;_ length, 1.6-5 n (26, vi, ix). 



Motility. Actively motile, dependent upon one, rarely 

 two polar flagella. 



Staining Properties. Not by Gram's method. 



Requirements as to Temperature, Oxygen, and 

 Nutrient Media. Strict aerobe, not particular as to 

 media, grows fairly rapidly and best at 25-30. 



Gelatin Plate. (a) Natural size. Deep: Roundish 

 to whetstone-shaped, yellowish. Superficial : At first like 

 the deep ; after forty-eight hours, 2 or 3 mm. wide, trans- 

 parent, lobulated, ragged, shining, yellowish-green. The 

 gelatin shows yellowish-green fluorescence (26, iv). It 

 gradually enlarges until its size is 1 sq. cm. 



(6) Magnified fifty times. Deep : Roundish, smooth- 

 bordered, light yellow, homogeneously shaded, usually 

 with a somewhat darker concentric ring (26, in). Super- 

 ficial : Both in the early and later stages it is indistin- 

 guishable from the colonies of Bact. typhi and coli except 

 from the fluorescence (26, n). There are here also mani- 

 fold variations. 



Gelatin Stab. Stab : Not characteristic, thread-like. 

 Surface growth : Lobulated, jagged, transparent, dull or with 

 a fatty luster, whitish -gray to yellowish-green. The 

 gelatin shows yellowish-green fluorescence (26, i). 



Upon agar, potato, milk, and bouillon it is indistin- 

 guishable from Bact. fluorescens. 



Remarks. Aside from the liquefaction of gelatin, the Bact. putidum 

 and Bact. fluorescens are scarcely different, and it appears entirely 

 justifiable to place them together under a Bact. fluorescens, with 

 forms a liquefaciens and ft non liquefaciens. We have also reached 

 the conclusion that the Bacillus fluorescens albus Zimmermann 

 and fluorescens longus Zimmermann, which we received directly 

 from Zimmermann and studied carefully, do not deserve to be desig- 

 nated as varieties. Both forms were identical with one isolated by us 

 from soil ; another, obtained from water, which we have cultivated for 

 years in our institute, now forms very long threads almost exclusively, 

 which we do not remember it to have done previously. A third form, 

 isolated by us from soil, corresponds somewhat with the Bacillus 

 fluorescens aureus Zimmermann, and is distinguished by a dirty 

 yellow growth upon agar and gelatin, but this characteristic is not 



