238 A MANUAL OF BACTERIOLOGY 



Bacillus pyocyaneus 



This is the organism found in green and blue pus, and it 

 also occurs on the surface of the body. Its presence in 

 wounds greatly retards healing, and occasionally a general 

 toxaemia may result from it. It has been met with in 

 otitis media and in the green pus of the pleural and peri- 

 cardial cavities. It is a slender bacillus measuring 3 to 

 4 jUL t frequently united in pairs and forming filaments. It 

 is actively motile, does not form spores, and is aerobic 

 and facultatively anaerobic. It does not stain by Gram's 

 method. On gelatin it grows freely with rapid liquefaction, 

 a greenish, fluorescent colour developing in the liquid, 

 while whitish flocculi of growth sink to the bottom. On 

 agar a whitish, moist layer develops, and the medium is 

 stained a greenish colour. On potato the growth is a 

 dirty brown or sometimes greenish. 



Milk is coagulated and a greenish colour develops. 

 Broth becomes turbid, and there is a slight film formation 

 with a greenish colour. Oxygen is necessary for the 

 development of the pigment, which is generally a mixture 

 of a blue pigment, pyocyanin, and a yellow one, 

 pyoxanthose. Pyocyanin (C 14 H 14 N 2 0) is said to be an 

 anthracine derivative ; it is soluble in chloroform, and 

 on oxidation yields pyoxanthose. 1 Various races of the 

 organism exist, differing in their pigment production. 



Subcutaneous inoculations of a small amount of a culture 

 produce local abscesses ; larger amounts cause oedema 

 with purulent infiltration of the tissues and death. Animals 

 can be vaccinated by means of small quantities of living 

 cultures or by sterilised cultures. Sterilised cultures will 

 prevent infection (experimentally) by anthrax if used 

 early that is to say, if an animal be inoculated with 



: 1 See Centr. f. BaU., xxv, p. 897 Journ. Exp. Med., September- 

 November 1899. 



