IX] BACILLUS 177 



become so changed, an organism results which is totally 

 unlike the typical thin smooth thread, but appears more like 

 a varicose thread in which the individuals are torula-like, 

 spherical, or oval cells, connected one with another by thin 

 bridges, the cells being three or more times as thick as the 

 typical rods (Fig. 49). In connection with this and the 

 former appearance, another appearance deserves notice, viz. 

 the segregation of the protoplasm in a chain or in individual 

 rods as separate spherical or oval granules, whereby the rods 

 and chains become transformed into varicose rods or fibres ; 

 in these the granules take and retain the dye easily, whereas 

 the bridges between them are less stained ; e.g., in tubercle 

 bacilli, leprosy bacilli, diphtheria bacilli, and others this 

 appearance is sometimes very regular and characteristic. 



Besides the above torula-like chains of the bacilli with or 

 without terminal club-shaped or pear-shaped enlargements, 

 another curious ajipearance deserves notice, that is the 

 branching that is observed in threads of tubercle bacilli 

 when grown for some time on glycerine Agar ; we find 

 here, besides torula-like threads, with club-shaped terminals, 

 others which show distinct sprouting and gemmation of 

 lateral cells,i these latter elongating into threads themselves 

 with club-shaped terminal enlargement. This suggests that 

 the tubercle bacilli are probably originally evolved from a 

 mycelial fungus and under certain conditions have a ten- 

 dency to revert to this state (Fig. 51). 



^ Report of the Medical Officer of the Local Government Board, 1890-91. 



