BACTERIOLOGICAL TECHNIC 6 1 



7 . Note any peculiar appearance in the micro- 

 scopical picture, especially involution 

 forms and the presence or absence of 

 capsules. If capsules are present, note 

 the method of demonstration. 

 V. Physiological characters. 



1. Relation to temperature: What is the 

 optimum temperature? 



2. Relation to free oxygen: aerobe, anaerobe, 

 facultative aerobe, or anaerobe. 



3. Relation to disinfectants, light, desicca- 

 tion, heat (thermal death-point). 



4. Pigment production: If present, +; if 

 absent, . In the former case, note the 

 color, diffusibility, solubility, influence of 

 acids and alkalis. 



5. Gas production in glucose media: to be 

 filled out only in case of actual observation. 

 In fermentation tubes note the growth in 

 either arm or both arms, recognized by tur- 

 bidity. Note the total percentage of the 

 gas formed in 24 and 48 hours. Reaction 

 may be tested by the addition of litmus 



TT 



solution. Gas formula expressed: T^T- 



CU 2 



6. Acid or alkali production in litmus milk. 



7. The production of indol or nitrites, or 

 both, is tested on the sixth day of observa- 

 tion in a culture in Dunham's pepton 

 solution or sugar-free broth. 



NOTE. Indol is a decomposition product of proteins and 

 belongs to the aromatic series. Nitrites result from reduction of 



