THE ORGANISMS OF SUPPURATION. 185 



Two forms of this bacillus have been distinguished, 

 one of which produces a blue colouring matter, 

 pyocyanin, and the other a yellow-brown one. In 

 addition, quite a large number of small differences 

 have been observed, but these appear to be so un- 

 important that a division into two species does not 

 seem to be justified. It is quite possible that the 

 different methods of cultivation play an important 

 part in bringing about these variations. 



This organism can hardly be confused with any 

 other; the fluorescent bacilli never cause such an 

 intense coloration as the Bacillus pyoeyaneus, and 

 the bacillus of blue milk {Bacillus cyanogenus) does not 

 liquefy the gelatine, and, moreover, the colour produced 

 by it is a more steely blue, or brown, which never 

 approaches a green. 



5. Micocroccus gonnrrhoece. The material for ex- 

 amining this organism, gonorrhoeal pus, is easily 

 obtained from any hospital. As the cultivation of 

 this micrococcus is most difl&cult, and can only be 

 accomplished in human blood serum, it is best not to 

 attempt it. We will therefore devote our attention 

 to observing its appearance in gonorrhoeal pus. 



A small quantity of the pus is spread out as evenly 

 and thinly as possible, without too much rubbing, 

 upon some cover-glasses, and is then left to dry 

 thoroughly in the air. The preparations are then fixed 

 and stained. The most suitable staining solution is a 



