THE CHAEACTEEISTICS OF BACTEEIA 



47 



C. Physiology. 



1. Relation to oxygen. 



2. Relation to light, desiccation, etc. 



3. Pigment production. 



4. Gas production. 



a. In shake culture. 



6. In fermentation tube : growth in open arm ; growth 



iu closed arm. 

 c. Ratio of H : CO.. 



B 





Fig. 26. Types of internal structure of colonies 



A, areolate ; B, gmmose ; C, moruloid ; D, clouded ; JE, gyrose ; F, marmorated ; 



G, reticulate 



5. Acid or alkaU production. 



a. Litmus milk. 



6. Reduction of nitrates to nitrites, to anunonia, or to free 

 nitrogen. 



7. Indol production. 



8. Habitat. 



