THE FAMILIES AND GENERA OF THE BACTERIA 199 



Genus 1. Mycobacterium Lehmann and Neumann, 1896a, p. 363 



Synonyms: Coccothrix Lutz 1886; Sclerothrix Metschnikoff 1888, not 

 Sclerothrix Kuetzing 1849; Mycomonas Jensen 1909. 



Slender rods which are stained with difficulty, but when once 

 stained are acid-fast. Cells sometimes show swollen, clavate or 

 cuneate forms, and occasionally even branched cells. Non- 

 motile, Gram-positive. No endospores. Growth on media 

 slow. Aerobic. Several species pathogenic to animals. 



The type species is Mycobacterium tuberculosis (Koch 1882) 

 Lehmann and Neumann. 



Genus 2. Corynebacterium Lehmann and Neumann 1896b, p. 350 

 Synonyms: Corynemonas Jensen 1909; Corynethrix Bongert 1901. 



Slender, often slightly curved, rods with tendency to club and 

 pointed forms, branching cells reported in old cultures. Barred 

 uneven staining. Not acid fast. Gram-positive. Non-motile. 

 Aerobic. No endospores. Some pathogenic species produce a 

 powerful exotoxin. Characteristic snapping motion is exhibited 

 when cells divide. 



The type species is Corynebacterium diphtheriae (Loeffler 

 1884) Lehmann and Neumann. 



Genus 3. Fusiformis Hoelling 1910, p. 240 



Synonym: Mantegazzaea Vuillemin 1913, not Mantegazzaea Trevisan 

 1879. 



Obligate parasites. Anaerobic or microaerophilic. Cells fre- 

 quently elongate and fusiform, staining somewhat unevenly. 

 Filaments sometimes formed; non-branching. Non-motile. No 

 spores. Growth in laboratory media feeble. 



The type species is Fusiformis termitidis Hoelling. 



Non-fusiform types like B. acne and the anaerobic types 

 found in Hodgkin's disease may for the present be tentatively 

 left in this genus. 



