80 



VETERINARY BACTERIOLOGY 



Spirochaeta. Spirochseta is defined as an organism with 

 long, thin, flexible spirals on which flagella are demonstrated 

 with difficulty, if at all. It is problematic whether the spirochsetae 

 belong to the true bacteria or are a group intermediate between 

 the bacteria and protozoa. Conclusive evidence on this subject 



Fig. 45. Types of spirochaetae. 



is still lacking. These organisms will be discussed with the 

 protozoa. 



Chlamydobacteriaceae. The classification here given is that 

 used by Jordan in his " General Bacteriology." Nomenclature 

 of the forms belonging to this group is badly mixed, and the same 

 terms have been used by different authors with reference to very 



Fig. 46. A, Leptothrix; B, Cladothrix; C, Nocardia; D, Actinomyces or Strep- 



tothrix. 



different organisms. Leptothrix is a sheathed organism which 

 shows no branching. Cladothrix is one which shows false 

 branching. This false branching arises through one of the inter- 

 calary cells dividing and pushing the cells lying above it to one 

 side, and developing thereafter as a terminal cell. Nocardia in- 

 cludes those forms in which there is true branching, and in which 



