DESCRIBING AN ORGANISM. 195 



1. Its source as air, water, or soil. If found in the 

 animal body, is it normally present or only in patholog- 

 ical conditions? 



2. Its form, size, mode of development, occurrence of 

 involution forms or other variations in morphology. 

 Grouping, as in pairs, chains, clumps, zoogloea ; presence 

 of capsule ; development and germination of spores ; 

 arrangement of flagella. 



3. Staining peculiarities especially its reactions with 

 Gram's (or Weigert's fibrin) stain, and peculiar or irreg- 

 ular modes of staining. 



4. Motility to be determined on very fresh cultures 

 and on cultures in different media. 



5. Its relation to oxygen is it aerobic, anaerobic, or 

 facultative? Does it develop in other gases, as carbonic 

 acid, hydrogen, etc. ? 



6. Both the macroscopic and microscopic appearance 

 of its colonies on nutrient gelatin and on nutrient agar- 

 agar. 



7. The appearance of its growth in stab and slant 

 cultures on gelatin, agar-agar, blood-serum, and on po- 

 tato. 



8. The character of its growth in fluid media, as in 

 bouillon, milk, litmus milk, rosolic-acid-peptone solu- 

 tion, and in bouillon containing glucose. 



9. Does it grow best in acid, alkaline, or neutral 

 media ? 



10. Is the normal reaction of the medium altered by 

 its growth ? Is its growth accompanied by the produc- 

 tion of indol ; is the indol associated with the coincident 

 production of nitrites ? 



11. Is its growth accompanied by the production of 

 gas, as evidenced by the appearance of gas-bubbles in 



