482 PATHOGENIC AEROBIC BACILLI 



tern, from green pus in the pleural cavity, from serum in the peri- 

 cardial sac, and from the spleen, in pure culture. 



Martha, Gruber, Maggiora, Gradenigo, Kossel, and Rohrer have 

 reported cases in which the Bacillus pyocyaneus has been obtained in 

 pure cultures from pus obtained from the tympanic cavity in middle- 

 ear disease. Kossel (1894) relates several cases in his own experience 

 which led him to the conclusion that, in children, the Bacillus pyocy- 

 aneus, through general blood infection or indirectly through the 

 absorption of its toxic products, may be the cause of death. 



The following varieties of this bacillus have been described by 

 bacteriologists : 



BACILLUS PYOCYANEUS /? (P. Ernst). 



Found in pus from bandages colored green. 



Morphology. Slender bacilli from 2 to 4 //long occasionally 5 to 6 n 

 and from 0.5 to 0.75 //broad; sometimes united in pairs, or chains of three 

 elements. 



Biological Characters. An aerobic, liquefying, actively motile, chro- 

 mogenic bacillus. Produces a yellowish-green pigment; when old cul- 

 tures are shaken up with chloroform and this is allowed to stand, three 

 layers are formed an upper, clouded, dirty-yellow layer ; below this is a 

 milky, pale-green layer ; and at the bottom a transparent, azure-blue layer. 

 Spore formation has not been demonstrated. Grows in the usual culture 

 media at the room temperature more rapidly at 35 C. Upon gelatin plates 

 colonies are formed resembling those of the well-known Bacillus pyocyaneus, 

 but liquefaction is more rapid. In gelatin stick cultures funnel-shaped 

 liquefaction occurs at the upper -part of the line of puncture by the third 

 day, and progresses more rapidly than is the case with. Bacillus pyocyaneus 

 under the same circumstances ; on the fifth day a bluish-green color is de- 

 veloped; by the twelfth day liquefaction has obliterated the entire line of 

 growth and extends to the margins of the tube; the liquefied gelatin for a 

 depth of about one centimetre has a dark emerald-green color, and a film 

 consisting of bacilli is seen upon the surface. Upon the surface of agar a 

 flat, greenish- white, dry layer is formed along the line of inoculation, and 

 the agar around, at the end of a week, acquires a bluish-green color. Upon 

 potato, at the end of three days, an abundant dry layer of a fawn brown 

 color has developed ; this is surrounded by a pale-green coloration of the 

 potato, and at points where the surface is fissured, an intense dark-green 

 color is developed; the growth on potato has a more or less wrinkled appear- 

 ance ; when one of the fawn-colored colonies is touched with the platinum 

 needle, the point touched, at the end of two to five minutes, acquires an in- 

 tense dark leaf-green color, which reaches its maximum intensity in about 

 ten minutes, and has faded out again at the end of half an hour. Ernst con- 

 siders this "chameleon phenomenon" the most characteristic distinction 

 between the bacillus under consideration and Bacillus pyocyaneus. In milk 

 a green color is developed at the surface, the casein is precipitated and sub- 

 sequently peptonized. 



Bacillus pyocyaneus peri car ditidis. Found by H. C. Ernst in 

 fluid obtained by tapping the pericardial sac of a man aged forty- 

 seven years. Fluid was drawn from the pericardial sac on four dif- 

 ferent occasions. The man subsequently "eloped." Ernst gives the 

 following description of this bacillus : 



