208 CLINICAL BACTERIOLOGY. 



dissolved in boiling distilled water looo, and filtered). The 

 bodies of the bacilli appear brown, and, as a rule, they contain 

 two blue granules, which have at once been intensely stained by 

 the first aniline dye, and have not yielded their color to the 

 vesuvin subsequently employed. These are the so-called Babes- 

 Ernst bodies (p. 19). The form, arrangement, and situation of 

 these bodies are considered as characteristic of the diphtheria- 

 bacillus under the following conditions : The preparations 

 must be made only from cultures that have grown upon L6 frier's 

 blood-serum (solidified at 100 C. 212 F. ) at a temperature 

 of 34 C. (93.2 F.) or 35 C. (95 F.), and never above 

 36 C. (96.8 F.). The cultures must not be less than nine 



Fig. 52. Bacillus diphtheriae, from a culture upon blood-serum ; X 1000 (Frankel 



and Pfeiffer). 



hours, and not more than from twenty to twenty-four hours, old. 

 At one end, more frequently at both ends, of the brown rod a 

 blue granule is then to be seen, and not rarely a third is visible in 

 the middle. These granules are oval in shape, and possess a 

 greater diameter than the bacillus itself, which, however, if the 

 whole appearance is to be considered of diagnostic significance, 

 must be distinctly visible in its entire length and form. 



It is further said to be characteristic of the diphtheria-bacillus 

 that the individual bacteria are arranged side by side like pali- 

 sades. As the most distinctive feature, M. Neisser considers 

 the appearance of impression-preparations from a serum-plate 

 six hours old that has developed at a temperature of from 34 

 C. (93.2 F.) to 36 C. (96.8 F.). In these there are 



