PATHOGENIC MICROORGANISMS 



Various observers, notably Nocard and Roux, 1 Mafucci, 2 and Klein, 3 

 have drm.mstratod branched forms of the tubercle bacillus. These ob- 

 servations, variously extended and confirmed, make it probable that 

 Bacillus tuberculosis is not a member of the family of schizomycetes, 



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FIG. 103. TUBERCLE BACILLI IN SPUTUM. 



but belongs rather to the higher bacteria, closely related to the actino- 

 myces. 



Staining. Tubercle bacilli do not stain easily with the ordinaiy 

 anilin dyes; to these they are made permeable only by long exposure 

 or by heating of the staining solution. Once stained, however, the dye 

 is tenaciously retained in spite of treatment with alcohol and strong 



1 Nocard et Roux, Ann. de 1'inst. Pasteur, 1887. 2 Mafucci, Zeit. f. Hyg., ii. 



* Klein, Cent. f. Bakt., 1890. 



