56 LABORATORY GUIDE IN BACTERIOLOGY 



2. Stab growth. 

 Vigor. 

 Extent. 

 Color. 



Granulation. 

 Outgrowths. 

 Coloration of medium. 

 Cloudiness. 

 Gas formation. 



V. Stab culture in dextrose agar. 



Describe like plain agar stab and in addition 

 always note presence or absence of gas 

 formation. 



VI. Stab culture in gelatin. 



Describe like agar stab, and in addition 

 always note presence or absence of lique- 

 faction. If liquefaction is present, it may 

 be saucer-shaped, turnip-shaped, conical, 

 funnel-shaped, horizontal (extending the 

 whole diameter of tube), sack-shaped. 

 Cloudiness and presence of sediment in 

 liquefied area, and color and shape of sedi- 

 ment, should be described. 



VII. Potato culture. 



Describe like agar slant, adding to it the 

 eventual discoloration of the medium, and 

 presence of gas bubbles. 



VIII. Litmus milk culture. 



Reaction (acid, alkaline, or neutral, as indi- 

 cated by color). , fc 



