THE CLASSIFICATION OF BACTERIA 201 



f Potato cultures never developing a red pigment. 

 Gelatin liquefied. Class XV, p. 266. 

 Gelatin not liquefied. Class XVI, p. 282. 

 ft Potato cultures developing a red pigment. Class XVII, 

 p. 285. 



b. Rods becoming spindle-shaped at sporulation, Clostridium type. 



Class XVIII, p. 287. 



c. Rods swollen at one end at sporulation, Tetanus type. Class 



XIX, p. 290. 

 2. Obligate anaerobic. 



a. Rods not swollen at sporulation. Class XX, p. 292. 



b. Rods becoming laterally swollen or spindle-shaped at sporula- 



tion. Class XXI, 295. 



c. Rods swollen at one end at sporulation. Class XXII, p. 302. 

 B. Chromogenic; produce pigment on gelatin or agar. Class XXIII, 



p. 304. 



CLASS I. WITHOUT ENDOSPORES. AEROBIC AND FACULTATIVE 

 ANAEROBIC. COLONIES ON GELATIN PLATES ROUNDISH, NOT 

 AMEBOID OR PROTEUS-LIKE. GELATIN NOT LIQUEFIED. DE- 

 COLORIZED BY GRAM'S METHOD. 



I. Gas generated in glucose bouillon. 

 A. Milk coagulated. B. Con Group. 



1. Indol produced. 



a. Phenol produced. 



1 . B. Marsiliensis Kruse. 



b. No phenol produced . 



2. B. colt (Escherich). 



3. B. Wardii. 



2. No indol produced. 



a. Gelatin colonies of a distinctly colon type, indistinguishable 



from those of B. colt. 



4. B. anindolicum Lembke. 



b. Gelatin colonies of a character intermediate between the colon 



and aerogenes types (bacteria intermediate between B. colt and 

 Bad. aerogenes). 



5. B. enter itidis Gartner. 



6. B. chologenes Kruse. 



7. B. toxigenus. 



