1030 COMPREHENSIVE KEY 



No gas produced in peptone; pleomorphic forms not uncommon 



Bacteroides p. J!^2J^ 

 (See also Sphaerophorus gulosus.) 



10. Halophilic, requiring more than 4 per cent salt for growth; gas produced from peptone 



Bacteroides p. 4^4 

 {B. halosmophilus) 

 Not halophilic 11 



11. Very pleomorphic; gas produced from peptone Sphaerophorus p. 44I 



{S. necrogenes and S. necrophonis and possibly S. varius and S. bullosus) 



Bifurcated cells; gas production from peptone doubtful Bacteroides p. 4^4 



{B. fur cos us) 



12. Acid produced from lactose 13 



No acid produced from lactose 16 



13. Motile Bacteroides p. 424 



(B. variegatus) 

 Non-motile 14 



14. Non-pleomorphic, /«si/orw cells growing poorly on plain agar (?) 



Fusobacterium p. 4^6 

 Not as above 15 



15. Gelatin liquefied; very pleomorphic on ordinary or blood agar 



Sphaerophorus p. 44-1 

 {S. glycolyticus) 



and Bacteroides p. 4^4 



{B. uncatus) 



Gelatin liquefied; not pleomorphic Bacteroides p. 424 



{Bacteroides exigmis, B. uniformis, B. tumidus and some strains of B. distasonis) 



Gelatin not liquefied Bacteroides p. 4^4 



16. Motile; fusiform rods; pleomorphic Fusobacterium p. 436 



{F. praeacutum) 

 Non-motile 17 



17. Very small rods capable of passing through a Chamberland L2 filter; acid produced 



from glucose, sucrose and mannitol; recorded from the respiratory tract of man 



Dialister p. 44O 

 Not as above 18 



18. Organisms dependent on serum or ascitic fluid for growth; pleomorphic 



Sphaerophorus p. 44^ 

 {S. floccosus and S. abscedens) 

 Not as above 19 



19. Slender, pointed rods Fusobacterium p. 4S6 



{F. polyinorphuui and F. vescum) 



Rods with rounded ends Bacteroides p. 4^4 



{B. cylindroides, B. capillosus, B. fragilis, B. perfoetans, B. uncatus and B. succino- 

 genes) 



20. Acid from fructose Sphaerophorus p. 44^ 



{S. siccus) 

 Not as above 21 



21. Organisms require serum or ascitic fluid for growth; pleomorphic 



Sphaerophorus p. 4P 

 (S. caviae) 



Not as above; not pleomorphic Bacteroides p. 4^4 



{B. putidus, B. putredinus and B. coagulans) 



