110 ESSENTIALS OF BACTERIOLOGY 



CHAPTER XVIII 

 BACILLUS TUBERCULOSIS AND ALLIED ORGANISMS 



THIS very important bacillus was first described, demon- 

 strated, and cultivated by Robert Koch, who made his in- 

 vestigations public before the Physiological Society of Berlin 

 on the twenty-fourth of March, in the year 1882. 



Synonyms. Mycobacterium tuberculosis. 



Fig. 47. Tubercle bacilli in sputum; carbolfuchsin and methylene-blue 

 (Zeiss one-twelfth oil-immersion). 



Origin. In various tuberculous products of man and other 

 animals and in the dust containing the discharges. 



Form. Very slender rods, slightly curved, 2 JJL to 4 ju in 

 length, about one-quarter the size of a red blood-corpuscle's 

 diameter, their ends rounded, usually solitary, often, how- 

 ever, lying in pairs in such a manner as to form an acute 

 angle. Sometimes they are S-shaped. In colored prepara- 



