Fig. 142. Bacillus diphtheriae, five hours Fig. 143. Bacillus diphtheriae, same cul- 



at 36 C. This shows only solid staining ture, eight hours at 36 C. This also shows 



forms. 



solid forms, many of them with parallel ar- 

 rangement. 



\/i <*'* 



N ' % ** 



.'-.'**V' ' 

 ' YX *T* -VJ 



A . J +-~^' 



-' : 'fr'\?~4^ 

 ,/^lAr/r 



* fc'^y N \ 



m > '-arVrA 



Fig. 144. Bacillus diphtheriae, same cul- 

 ture, 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. 145. Bacillus diphtheriae, same cul- 

 ture, fifteen hours at 36 C. The bacilli 

 stain more unevenly and the granules are 

 larger. 



r^- ^ 



v -^ 



Fig. 146. Bacillus diphtheriae, same cul- 

 ture, 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 char- 

 acteristic clubbing of the distal ends. 



(Photomicrographs by Mr. Louis Brown. 



All of the preparations were made from growth on blood-serum.) 

 " Jour, of Med. Research.") 



455 



Fig. 147. Bacillus diphtheriae, 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. 



The magnification is the same in all X 2000. 

 (Francis P. Denny, in 



