DESCRIPTION OF PLATE III. 



FIG. i. Bacillus diphtheriae, five hours at 36 C. This shows only solid 

 staining forms. 



FIG. 2. Bacillus diphtheriae, same culture, eight hours at 36 C. This 

 also shows solid forms, many of them with parallel arrangement. 



FIG. 3. Bacillus diphtheriae, same culture, twelve hours at 36 C. The 

 bacilli stain faintly at their ends, and in some small granules are seen at 

 the tip of the faintly stained portions. 



FIG. 4. Bacillus diphtheriae, same culture, fifteen hours at 36 C. The 

 bacilli stain more unevenly and the granules are larger. 



FIG. 5. Bacillus diphtherias, same culture, twenty-four hours at 36 C. 

 This shows clubbed and barred forms as well as granular forms. At the 

 lower part of the field is a paired form which shows the characteristic 

 clubbing of the distal ends. 



FIG. 6. Bacillus diphtherise, forty-eight hours at 36 C. This is the 

 same bacillus as in the preceding figures, but from a culture where the 

 colonies were discrete. It shows long filamentous forms. 



(Photomicrographs by Mr. Louis Brown. The magnification is the 

 same in all X 2000. All of the preparations were made from growth on 

 blood-serum.) 



(Francis P. Denny, in Journal of Medical Research.} 



