Il6 MORPHOLOGY AND CULTURE OF MICROORGANISMS 



IV. SPIRILLACE^: 



Flagellum single (rarely 2 or 3) i. Vibrio 



Flagella tufted (5 to 20) 2. Spirillum 



V. COCCACE.E 



Abundant red-pigmented growth on agar. . 7. Rhodococcus 

 Not as above 

 Gram negative 



Normally in pairs of flattened cells; 

 growth on plain agar scanty, never 



bright yellow i. Neisseria 



Normally in plates, packets, or irregu- 

 lar masses; growth on plain agar 

 abundant, pigment definitely 

 yellow 



Cells in regular packets 6. Sarcina 



Cells not in regular packets 5. Micrococcus 



Gram positive (exceptions rare and not 



easily confused with above genera) 

 Cells normally in chains, sometimes in 

 pairs (especially in acid environment) 

 never in large irregular masses. 

 Gelatin rarely liquefied. Growth on 

 plain agar usually translucent, never 



heavy, never yellow or orange 2. Streptococcus 



Cells normally in groups and masses; 

 (occasionally in plates in Albo- 

 coccus) chains short and irregular, 

 if present. Gelatin often lique- 

 fied. Agar growth abundant, 



white to orange 



Pigment orange (rarely lacking); 



gelatin often liquefied actively.. . .3. Staphylococcus 

 Whitish to porcelain white; liquefac- 

 tion less vigorous 4. Albococcus 



VI. BACTERIACE^E 



Plant pathogens 2. Erwinia 



Not as above; saprophytes or in animal 



habitats (intestines, tissues, etc.) 

 Usually motile and exhibiting active 

 fermentative powers; typically para- 

 sitic in intestines of man and higher 

 animals; growing well on ordinary 

 media. . i. Bacterium 



