COMPREHENSIVE KEY 1001 



9. Gram-positive 10 



Gram-negative 11 



10. Organisms occur as cocci under anaerobic conditions in neutral media; in media be- 



coming acid, they assume a diphtheroid form; extremely pleomorphic under aerobic 

 conditions; produce propionic acid from lactic acid. . . Propionibacterium p. 569 



Not as above possibly Mycococcus p. 707 



Note: The description of Mycococcus has a strong resemblance to that of 

 Arthrobacter in the earlier literature, and the two generic names may be syno- 

 nj^ms. Micrococcus cinnabareus and M. rhodochrous are included here. 



11. Anaerobic; non-motile; Gram -negative; principally rod-shaped cells exhibiting a coc- 



coid phase; recorded from genital and alimentary tracts of man and other animals 



Sphaerophorus p. 44^ 

 Aerobic 12 



12. Obligate halophiles requiring 16 to 30 per cent salt for growth; not luminescent 



Halobacterium p. 207 

 Not obligate halophiles 13 



13. Parasites attacking erj'throcj-tes and endothelial cells of man; extremely pleomorphic 



within the host; straight and curved rods, ring forms and cocci occur; grow in semi- 

 solid rabbit serum agar mainly as rods and cocci ; polar flagella 



Bartonella p. 969 

 Note: This genus is selected as an example only of a large group of intracellular 

 parasites which are pleomorphic and have coccal stages. Only an odd species 

 has been cultivated. For other species, see the Manual keys for the class 

 Microtatobiotes p. 933 



Animal parasites; non-motile; produce tularemia or tularemia-like infections in ro- 

 dents Pasteurella p. 895 



Not as above 14 



14. Bioluminescent when grown on fish agar or meat infusion agar containing 3 per cent salt 



Photobacterium p. 193 



Organisms not fitting into anj- of the above groups are probably pleomorphic forms of 



rod-shaped cells; proceed to Section E p. 1003 



15. Organisms parasitic within the cj^oplasm or nucleus of flagellated protozoa 16 



Not as above 17 



16. Parasitic on the nucleus or nucleolus Caryococcus p. 927 



Parasitic in the cj'toplasm of Trichomonas batrachorum Micrococcus p. 929 



{M. batrachorum) 



17. Strict autotrophs; will not grow on organic media; oxidize ammonia to nitrite or nitrite 



to nitrate 18 



Heterotrophic 19 



18. Oxidize ammonia to nitrite; non-motile; not encapsulated . . Nitrosococcus p. 69 

 Other than above; proceed to Section G p. 1008 



19. Obligate anaerobes 20 



Aerobic or microaerophilic 23 



20. Gram-variable; cells occur singly or in masses; ferment acetate vigorously with the 



production of methane; discovered in mud Methanococcus p. 473 



Not as above 21 



21. Gram-positive 22 



Gram-negative ; arranged in pairs and clusters ; diameter of cells varies between species 



from 0.3 to 2.0 microns Veillonella p. 485 



22. Organisms arranged in pairs or chains only Peptostreptococcus p. 533 



Organisms arranged in cubical packets Sarcina p. 467 



