190 APPLIED BACTERIOLOGY 



if the streaks are found to show whitish colonies, many of 

 them separate from the actual line of inoculation, and 

 presenting on staining the appearance of an immense 

 number of small short rods, slightly clubbed at the ends, 

 there is little doubt but that they are the true Klebs- 

 Loffler bacilli. 



According to Dr. Cartwright Wood, an immediate 

 diagnosis can be made by direct staining in 60 per cent, 

 of cases of diphtheria. 



Pseudo - Diphtheria Organisms. — Peters (British Medical 

 Journal, 1895, vol. ii., p. 1557, Path. Soc.) has described the 

 following varieties of the diphtheria bacillus: (1) LongKlebs- 

 Loffler bacillus ; (2) short diphtheria bacillus ; (3) short 

 pseudo-diphtheria bacillus. The latter is widespread and 

 non-virulent, and he regards it as possibly being uncon- 

 nected with the diphtheria bacillus, though closely re- 

 sembling it. 



Hoffman (Wiener med. Wochenschr., 1888, Nos. 3 and 4), 

 Koux, and Yersin (Ann. de I'Institut Pasteur, iv., 1890), 

 and others, have also described pseudo-diphtheria bacilli, 

 which are non-virulent in character, and are shorter and 

 plumper than the normal Klebs-Loffler organism, but are 

 otherwise similar in cultural characters. 



Klein (Local Government Board Report, 1889) has 

 described a pseudo-diphtheria bacillus which might be con- 

 fused with the Klebs-Loffler bacillus, but can be distinguished 

 from it by growing the two organisms on gelatine, when 

 it will be found that the pseudo-diphtheria bacillus grows 

 much more slowly. He states, however, that its occurrence 

 is so rare that it is usually neglected. 



Eoux and^Yersin have obtained attenuated varieties of 

 the diphtheria bacillus by cultivating it at a temperature 

 slightly above blood-heat and freely supplied with air, 

 and they have suggested that a similar attenuation of 



