96 SPECIAL BACTERIOLOGY 



the cocci, their position in the pus cells, and their negative reaction 

 with the Gram staining method, allow the diagnosis of gonorrhoea 

 to be accomplished with positive certainty. The absence of the 

 gonococci in microscopical specimens of urethral discharge must be 

 accepted with caution, as the gonococci are sometimes situated deep 

 in the mucosa of the urethra, and often absent in the superficial 

 discharge. It is therefore necessary in doubtful cases to irritate the 

 urethra and stimulate the discharge. If the secretion after repeated 

 examination, also .with previous irritation of urethra, is found free 

 from gonococci (numerous other cocci are usually present), then the 

 gonorrhoea can be considered terminated, and only a urethritis 

 catarrhalis existent. 



BACILLUS PYOCYANEUS. 



(Bacillus of green pus. Microbe du pus bleu. Boot. Aeruginosum.) 



This bacillus is found in green or blue-coloured pus, especially in 

 green-coloured bandages, from which pure cultures are easily obtained 

 with plate cultures. 



Microscopical Appearances. Small thin bacilli about the length 

 of the bacillus of mouse septicaemia, but a little thicker, and in cultures 

 often form small chains, occasionally growing into filaments. 



Motility. Strongly motile, possessing only one flagellum (mono- 

 tricha). 



Spore Formation does not exist. 



Staining Reactions. It stains readily with the ordinary aniline 

 dyes, but not by the Gram method. 



Biological Characters. This organism is a facultative anaerobe, 

 growing both at room and incubator temperature. 



On Gelatine Plates, flat, irregular, circumscribed colonies develop with 

 radiating borders ; the gelatine is liquefied quickly, the surrounding 

 media exhibiting a green fluorescence. 



In Gelatine Stab Cultures the medium is liquefied quickly. 



On Oblique Surface Agar a whitish coating is formed, and the under- 

 lying medium is coloured green. 



On Glycerine Agar the inoculated medium exhibits at first a blue colour, 

 which gradually becomes darker. 



On Potatoes a greenish-yellow or brownish growth takes place, the 

 surrounding surface being coloured green. 



Bouillon is clouded. 



Milk is coagulated and peptonized. 



This organism produces pyocyanin and a fluorescent green colouring 



