IMPORTANT PATHOGENIC BACTERIA 133 



The virulence of B. mallei seems not to diminish in 

 laboratory cultures, and careless handling may affect all 

 those who are engaged in work in the same place. 

 Those who desire to study this organism will find 

 directions in the following section. 



Inoculate agar slants from laboratory cultures of 

 B. melitensis and Blastomyces dermatitidis. 



Carry these cultures through the usual routine. 



SECTION iiB 



In this section the following organisms have been 

 included: Spirillum cholerae, Bacillus mallei, Bacillus 

 influenzae, Micrococcus meningitidis (meningococcus). 



A separate section has been devoted to these organ- 

 isms so as to enable the instructor to omit them if he 

 deems it advisable. The Sp. cholerae and B. mallei 

 are dangerous organisms to be manipulated by ele- 

 mentary students, and unless there is sufficient super- 

 vision accidents of grave consequences are liable to 

 happen. The Sp. cholerae may be studied in the 

 usual routine manner and the test for the so-called 

 cholera-red reaction (indol reaction) and SchotteUus 

 enriching method (see p. 130) added. B. mallei should 

 also be studied in the usual manner and a demonstra- 

 tion of its infectiousness made on guinea-pigs. 



B. influenzae requires special media for study, blood 

 agar being the most suitable. The meningococcus 

 grows to some extent on ordinary media. Stains 

 with methylene blue and according to Gram's method 

 are instructive, showing the resemblance of this organ- 

 ism to the gonococcus. 



