2 SUGGESTIONS FOR USE OF MANUAL 



In this key examine A. Cells rigid, not flexuous. This indicates our or- 

 ganism as its cells remain constant in form. 



We next examine 1. Cells single, in chains or masses. Not branching and 

 mycelial in character. Not arranged in filaments. Not acid fast. As the 

 organism in question occurs as single cells or at most as short chains and is 

 not acid fast, this indicates that it belongs to the Order Eubacteriales. 



We now examine a. Do not possess -photo synthetic pigments. Cells do not 

 contain free sulfur. As our organism is unpigmented and the cells do not 

 contain free sulfur, this indicates that our organism belongs to the Sub-order 

 Eubacteriineae. We note that the key to this suborder is on page 

 67. 



We next attempt to ascertain the family to which the organism belongs 

 by tracing it through the key to the familiesof the Sub-order Eubacteriineae, 

 p. 67. 



I. No endospores indicates our organism. We proceed to A. Can develop 

 on inorganic media. As the organism cannot grow without organic carbon, 

 we turn to B. Cannot develop on inorganic media. 



This corresponds with the physiology of our organism; so we turn to 



1. Polar flagellate, etc. As our organism is peritrichous, we proceed to 



2. Large oval, pleomorphic cells sometimes almost yeast-like in appearance. 

 Free living in soil. Fix free nitrogen. As this does not correspond with the 

 morphology or physiology of our organism, we next examine 3. Peritrichous 

 or non-motile rods, and cocci. This corresponds with the characteristics of 

 our organism. 



We turn to a. Heterotrophicrodswhichmaynot require organic nitrogen for 

 growth. Usually motile with one to six or moreflagella. Usually form nodules 

 or tubercles on roots of plants, or shoio violet chromogenesis. 



This again does not indicate our oi canism ; so we turn next to aa. Heter- 

 otrophic rods or cocci iDhich utilize organic nitrogen and usually carbohydrates. 

 As our rod-shaped organism prefers a medium containing organic nitrogen, 

 we proceed to b. Spherical cells in masses, tetrads and packets. 



This does not correspond to the morphology of our organism, and we now 

 proceed to bb. Spherical cells ivhich grow in pairs and chains; and rods. 

 This includes our rod-shaped organism; so we turn to c. Gram-positive 

 cocci and rods. Non-motile. Since these are not the characteristics of our 

 organism, we turn to cc. Gram-negative rods. When motile, from four to 

 many peritrichous flagella. 



Our organism is Gram-negative and peritrichous; so we proceed to d. 

 Grow well on ordinary media containing peptone. Aerobic to factdtative 

 anaerobic. 



This corresponds with the characteristics of the organism we have 

 studied; so we turn next to e. Gram-negative, straight rods which ferment 



