PLATE I 



FIG. 1. 



Cover-glass preparation of pericardial exudate, showing 

 bacillus pyoeyaneus stained blue, and the bacillus tuber- 

 culosis stained red. (Ernst.) 



FIG. 2. 



t , 



V * 



Urethral discharge from a ease of gonorrhoea, showing 

 gonococei enclosed in pus corpuscles, and lying free in the 

 discharge. Stained with methylene blue. (C. E. Simon.) 



