262 PATHOGENIC BACTERIA. 



Bacillus Pyocyaneus. 

 In some cases the pus evacuated from wounds exhibits 

 a peculiar bluish or greenish color, from the presence of 



wi • US**.* « 



J v T , *«v 



Fig. 57. — Bacillus pyocyaneus, from an agar-agar culture; x 1000 (Itzerott 



and Niemann). 



the Bacillus Pyocyaneus (Figs. 57, 58). This is a short, 

 delicate bacillus of small size, measuring 0.3 : 1-2 /•«, ac- 

 cording to Fliigge, frequently united in chains of four or 

 six. It has round ends, is actively motile, has one 

 terminal flagellum, does not form spores, and can exist 

 with or without oxygen, though it is an almost purely 

 aerobic organism. 



It closely resembles a harmless bacillus found in 

 water, the Bacillus fluorescens liquefaciens, from which 

 Ruzicka 1 thinks it probably descended. It stains well 

 with the ordinary solutions, but does not retain the color 

 by Gram's method. 



The superficial colonies upon gelatin plates form small, 

 irregular, ill-defined collections, which produce a fluores- 

 cence of the neighboring gelatin. The gelatin softens 

 gradually, and about five days elapse before liquefaction 

 is complete. 



1 Centralbl.f. Bakt. u. Parasitenk., July 15, 1898, p. XI. 



