BACTERIUM VULGARE. 297 



characteristic ; later, there is tube-shaped liquefaction. 

 The surface growth at once forms a saucer-shaped lique- 

 faction, and later the liquefaction becomes cylindric. The 

 liquefied material is turbid or cloudy (31, i). (The picture 

 is a little too violet. ) 



Agar Plate. (a) Natural size: Entirely non-character- 

 istic. The surface colonies are delicate grayish-white; the 

 deeper, yellowish-white (31, in). 



(&) Magnified sixty times. Deep colonies : Roundish, very 

 crumbly, later often moruloid (33, iv below). Super- 

 ficial : Delicately transparent, exceedingly finely granular, 

 at the center yellowish and becoming colorless toward the 

 periphery. The periphery assumes all possible irregular 

 forms, from the wandering outward of the bacteria (32, 

 vn). At first it is always roundish (31, iv). Typical, 

 elongated, sausage forms, etc., such as occur on gelatin, 

 have never been observed by us. 



Agar Stab. Stab : Not characteristic, thread-like. 

 Surface growth : Gray, slimy, moist, transparent. 



Agar Streak. Veil-like, thin, transparent, moistly 

 glistening growth, which already after twelve hours has 

 overgrown the entire surface. Water of condensation very 

 cloudy, whitish-yellow. 



Bouillon Culture. Very cloudy, abundant precipi- 

 tate. 



Milk Culture. Firmly coagulated after two to three 

 days, and later again liquefied. Still later, milk becomes 

 yellowish and feebly acid. 



Potato Culture. Very scanty growth; whitish-yellow, 

 usually limited to the inoculation streak, somewhat 

 crumbly, dull or with a fatty luster, somewhat elevated. 



Chemical Activities. 



(a) Odoriferous substances: Albuminous bodies under- 

 go putrefactive decomposition with very abundant foul 

 odor, and a strong alkaline reaction. 



(6) Formation of gas and acid from carbohydrates: It 

 forms abundant gas from grape-sugar; according to Th. 

 Smith, still more from cane-sugar, and none from milk- 

 sugar. According to Smith, the gas consists of one-third 

 CO 2 and of two-thirds H 2 . Upon sugar media no foul 

 odor is present (Kuhn). 



