THE CLASSIFICATION OF BACTERIA 321 



Gelatin colonies. In 2 days, 1.5 mm., grayish white, translucent; micro- 

 scopically, with brownish centres, borders thin, with radiate structure ;. 

 later show a greenish white blue green fluorescence. 



Gelatin stab. Liquefaction slow, crateriform, with a blue green fluorescence. 



Agar slant. Growth grayish, translucent ; agar fluorescent. 



Bouillon. Turbid, with a slight pellicle and a blue green fluorescence. 



Potato. Growth brownish, elevated, spreading. 



Litmus milk. Coagulated slowly, decolorized slowly. 



Glucose bouillon. No gas. Indol doubtful. 



Habitat. Water. 



-D 6td 



28. Ps. pyocyanea. (Gessard) Migula 



B. pyocyaneus Gessard : De la pyocyanine et son microbe, These de Paris, 1882. 

 Ps. pyocyanea Migula : Die Natiirlichen Pflanzenfam., 1896. 



Morphology. Bacilli 0.4: 1.4-6 /x, yariable. A polar flagellum. Stain by 

 "Gram's method. 



Gelatin colonies. Deep: round, oval, yellowish white greenish yellow, often 

 moruloid. Surface: round, entire, yellowish; later, the borders become 

 irregular and coli-like ; often beset with hairs, or fringed ; becoming 

 sunken, with an irregular, variable structure, gray or greenish gray, irregu- 

 lar, ragged, or coarsely granular. 



Gelatin stab. Liquefaction crateriform, becoming saccate, with a greenish 

 yellow-blue green fluorescence ; contents granular, flocculent. 



Agar colonies. Deep: round, oval, entire, undulate, granular, yellow green- 

 ish yellow. Surface: round, entire, glistening, greenish white yellowish ; 

 microscopically, round, entire, granular, moruloid, yellow greenish 

 yellow. 



Agar slant. Growth soft, glistening, spreading, yellowish green greenish ; 

 the agar shows a strong yellow green fluorescence. 



Bouillon. Turbid, with a pellicle, and a strong yellow green fluorescence. 



Milk. Coagulated, becoming fluid and alkaline, with a yellow green fluores* 

 cence. 



Potato. Growth yellowish, moist, glistening, slightly raised, becoming brown- 

 ish yellow brown. Indol negative. H 2 S negative. 



Glucose bouillon. Acid, no gas. Nitrates reduced to nitrites. 



Pathogenesis . Subcutaneous inoculation of i cc. of a virulent bouillon culture 

 into guinea pigs and rabbits causes a purulent infiltration and inflamma- 

 tory oedema at the point of inoculation, and death in some cases ifi 24 

 hours. Intraperitoneal inoculations cause peritonitis and death. With 

 small doses only local inflammation, and recovery. 

 Y 



