PATHOGENIC BACTERIA 165 



dressings containing the Bacillus pyocyaneus are washed in 

 chloroform, the pigment is dissolved and crystallizes from the 

 chloroform in long needles. It is soluble in acidulated water, 

 which is turned red thereby, and when neutralized, the blue color 

 returns. It has no pathogenic action. It is an aromatic com- 

 pound. The bacillus has no especial action on the wound, and 

 is found sometimes in perspiration of healthy persons. 



Bacillus Pyocyaneus /? (Ernst). A bacillus found in 

 grayish, pus-colored bandages. 



Fig. ioo. Morax-Axenfeld diplobacillus from conjunctival exudate during 

 course of subacute conjunctivitis (obj. B. and L., one-twelfth oil-immersion) 

 (Boston). 



The only especial difference between this and the above is the 

 formation of brownish-yellow pigment instead of pyocyanin. 

 The form and appearance of cultures otherwise the same. 



Koch-Weeks' Bacillus (1883-87). Cause of epidemic 

 conjunctivitis, or "pink eye"; found in the secretion. 



Form. Very minute bacillus, resembling the influenza 

 bacillus; non-motile. (See Fig. 99.) 



Growth. They grow best on blood-serum agar, but very 

 sparsely in minute transparent colonies; non-liquefying. 



