THE CLASSIFICATION OF BACTERIA 315 



B. Gelatin not liquefied. 



21. Ps. turcosa (Zimmerman). 

 II. Pigment blue-violet on gelatin or agar. 



A. Gelatin liquefied. 



1 . On potato, pigment violet. 



22. Ps.janthina (Zopf). 



2. On potato, growth grayish blue — blue green. 



23. Ps. coerulea (Voges). 



3. On potato, growth dark blue — blue black. 



24. Ps. Smithii. 



B. Gelatin not liquefied. 



25. Ps. indigofera (Voges). 



26. Ps. Berolinensis (Classen) Migula. 



17. Ps. puUulans (Wright) 



B.pullulans Wright : I.e., 445. 



Morphology. Bacilli small, short, in pairs. Flagella several, polar. 



Gelatin colonies. In 2-3 days 2 mm., yellowish gray, slightly elevated, trans- 

 lucent. Microscopically, with yellowish centres and colorless margins, 

 sausage-shaped granules on lower side of colony, surrounded by a zone 

 of liquefied gelatin. 



Gelatin stab. Surface growth raised ; liquefaction napiform. 



Agar slant. Growth yellowish, translucent. 



Glttcose bouillon. No gas. Nitrates not reduced. Grow at 36°. Indol pro- 

 duced. 



Habitat. Water. 



18. Ps. annulata (Wright) 



B. annulaius Wright : I.e., 443. 



Morphology. Bacilli small; occur singly, in pairs, and as long forms. Fla- 

 gella several, at one or both ends. 



Gelatin colonies. In 3-4 days, 2-3 mm., round ; centres yellowish, edges 

 indistinct — somewhat fringed ; liquefaction saccate. 



Gelatin stab. Liquefaction crateriform, yellowish flocculi, a slight pellicle. 



Agar slant. Growth yellowish, translucent, glistening. 



Bouillon. Turbid, with a yellow pellicle. 



Litmus milk. Coagulated, decolorized. Indol slight. No growth at 36°. 



Habitat. Water. 



