546 PATHOGENIC AEROBIC BACILLI 



ORIGIN. Pericardial fluid, containing also bacilli of tuberculosis. 



FORM AND ARRANGEMENT. Small straight bacilli, with rounded ends, 

 three or four times as long as broad, and on most media slightly larger than 

 the Bacillus pyocyaneus of Gessard, occurring within the cells in the origi- 

 nal fluid, and sometimes showing two or three end to end, but never observed 

 in long chains. 



MOTILITY. Actively motile in hanging-drop culture. No cilia or flagel- 

 la have been demonstrated. 



GROWTH Gelatin : Plates. Colonies appear at the end of thirty-six to 

 forty-eight hours as fine white points in the interior, and upon the surface of 

 the medium ; edges are sharply defined ; soon there appears a circular zone 

 of liquefaction, finally passing through the stratum of the medium with 

 the colony at the bottom. Under a low power the centre of the colony may 

 be of a brownish color. On the second day a greenish tinge may be seen 

 about the individual colonies on the surface which spreads through the 

 entire medium. The plates may always be distinguished from those of the 

 Bacillus pyocyaneus of Gessard by the bluish-green when contrasted with 

 the yellowish-green color of this latter. 



Gelatin: Needle Cultures. At the end of twenty-four hours a small, 

 saucer-shaped depression of liquefaction at upper end of needle track, which 

 gradually spreads and deepens until the liquefaction extends straight across 

 the tube, and about half-way down the needle track. A bluish-green fluores- 

 cence appears about the liquefied portion at the very upper part of the gela- 

 tin, later changing into a yellowish green. The colony is deposited as a 

 yellowish, heavy sediment at the bottom of the liquefied portion, the upper 

 part of which is clear. A small, whitish growth occurs along the remainder 

 of the needle track. Old cultures, in which a certain amount of evapora- 

 tion has occurred, assume a very dark greenish-black color. 



Agar-agar. Along the needle track appears a flat, dry colony of a dirty 

 grayish- white color spreading out upon each side of the needle track and 

 growing at first upon the surface of the water of condensation, later depos- 

 iting a white sediment at the bottom. From the first there may be detected, 

 by reflected light, a metallic lustre on the surface of the colony in places, 

 which metallic sheen later spreads over the whole colony and furnishes a 

 marked differentiating point. In addition to this, within twenty-four to 

 forty-eight hours at 37 C., there appears a green fluorescence throughout 

 the whole of the medium, which increases slowly to a marked bluish-green 

 color, and never assumes the nut-brown of the Bacillus pyocyaneus of 

 Gessard upon the same medium. The colony is not especially viscid. 



Potato. There appears a reddish-brown colony along the needle track, 

 elevated and moist, confined to the line of the needle. It presents no change 

 of color upon touching with the needle, but certain specimens (as do some of 

 the Bacillus pyocyaneus) develop later a heavy green color extending over 

 the whole surface of the potato, which later changes almost to black. 



Bouillon. Twenty-four hours at 37 C. gives a growth, especially on the 

 surface, which is a wrinkled scum ; no cloudiness of the bouillon, and a very 

 faint greenish fluorescence one centimetre below the surface. At this time 

 it differs from the Bacillus pyocyaneus of Gessard, in that the latter shows 

 cloudiness of the medium all through. Later the same cloudiness appears in 

 bouillon cultures of this new bacillus, together with a whitish sediment de- 

 posited at the bottom of the tube, and then the cultures are indistinguishable 

 from each other. The same changes, but slower, occur at room tempera- 

 ture. 



Peptone. One, 3.5, and six-per-cent solution. Twenty-four hours at 37 

 C. gives a faint bluish tinge at upper edge of medium with very faint cloudi- 

 ness ; later (in one or two weeks) there forms a marked scum upon the sur- 

 face that is difficult to break up by shaking, and the whole medium assumes 

 a grass-green color of more or less intensity, and not seen on other similar 

 bacilli. The shape and size of the organism, under the microscope, differ 



