THE CLASSIFICATION OF BACTERIA 67 



Gelatin colonies. In 48 hours, minute points. Microscopically irregular, dark 

 granular in centre, 0.1 mm. 



Agar colonies. Deep colonies : irregular oval, coarsely granular, dark yel- 

 lowish in centre, with a clear erose border. Surface colonies : 24 hours, 

 minute points. Do not increase in size. 



Potato. A moist glistening thin growth composed of small white colonies. 



Milk. In 2-3 days coagulated, acid. 



Agar slant. A thick glistening layer. 



Habitat. Isolated from a case of enteritis. 



24. Str. phytophthorus Frank 



Die Bakterienkrankheiten der Kartoffeln : Centralblatt f. Bakteriologie, Zweite Abt, V. 1899. 



Morphology . Cocci 0.5 /x; occur singly, in twos, and short chains. 



Gelatin colonies. Flat, roundish, lobate, white, rosette-like, sunken in the 



centre. 

 Habitat. Associated with a rot and blight of the potato. 



25. Str. Grotenfeltii 



Str. acidi-lactici, Grotenfelt: Fortschritte d. Medizin, VII, 124. 



Morphology. Cocci round-ellipsoidal, 0.5-1.0: 0.3-0.6/1. 

 Gelatin colonies. Round, white. 

 Gelatin stab. A good growth in depth. 

 Milk. Coagulated, acid ; no gas ; lactic acid. 

 Habitat. Milk. 



26. Str. proteus 



Str. No. 52 Conn : Report Storr's Ag. Expt. Sta., 1894, 81. 



Morphology. Cocci 0.3 /x, forming chains which have a tendency to arrange 



themselves in rings. Grow at 35 C. 

 Gelatin colonies. Smooth, raised, very white, becoming 1.0 mm.; not 



spreading. 

 Gelatin stab. In depth a good growth ; on the surface growth snow-white, 



raised. 

 Agar slant. Growth smooth, thick, white, glistening. 

 Milk. Coagulated, acid. 

 Bouillon. Turbid ; a slight sediment. 

 Habitat. Milk. 



