



PLATE III. — Photographs of fixed cells of a colon bacillus stained by 

 the Giemsa technique: i, untreated cells; 2, fixed cells treated 

 with ribonuclease prior to staining; 3, treated with ribo- 

 nuclease and deoxyribonuclease. Ribonuclease removes cyto- 

 plasmic PNA responsible for the overall staining in i and 

 enables the presence of chromatinic (nuclear) bodies to be 

 shown (2). The latter are composed of DFNA and are not 

 present in the cells treated with deoxyribonuclease (3) 



