THE CLASSIFICATION OF BACTERIA 359 



Glycerin agar slant. In 2 days, at 37°, small, delicate, watery colonies, be- 

 coming confluent. Growth rather raised, often with a yellowish tinge. 

 In the water of condensation, which is clear, small particles which sink. 



Potato. At 37° a thick grayish white growth along the line of inoculation. 



Milk. Becomes acid in 2-3 days. 



Bouillon. Medium clear ; a grayish white membrane and a stringy sediment ; 

 no odor. 



Gelatin slant. In 4-5 days, at 20°, a grayish white thick growth along the 

 line of inoculation ; no liquefaction. 



Gelatin stab. A good growth along the line of stab. 



Pathogenesis. Intraperitoneal inoculations of guinea pigs cause death in 4-6 

 weeks, with the same macro-pathological picture as in tuberculosis. 



Habitat. Found in hay dust in lofts. 



19. Mycobact. friburgensis (Kom) 



B.friburgensis Kom: Centralblatt f. Bakteriol., XXV, 1899, 532. 



Morphology . Bacilli in bouillon vary from those simulating B. coli to longer 



and slightly bent rods. On agar the rods are rather thinner ; on old agar 



and serum cultures, coccothrix forms. On potato, cocci, diplococci, and 



short rods or partly bent bacilli of variable thickness, also clavate forms. 



In the animal body, tubercle and coli forms ; also branched individuals. 



Stain poorly with ordinary aniline colors, well with aniline and carbol 



fiichsin, and withstand decolorization for one minute in 10 per cent 



H2SO4. Stain by Gram's method. 

 Agar colonies. Deep: round — elongated, granular. Surface: round, grayish 



white, becoming sunken in the centre. 

 Gelatin stab. In depth, growth slight, uniform ; on the surface, growth white, 



and rather flat and lobate. 

 Glycerin agar slant. In 2-3 days, at 37°, growth thick, glistening, rough, 



crumpled, with a membrane on the water of condensation. 

 Bouillon. On the surface, a thick membrane. Cultures have a bad odor. 



No growth in acid bouillon. 

 Glucose bouillon. Grow only in the open end ; no gas. Indol slight, and 



produced only in glycerin bouillon. 

 Milk. In 6 days unaltered ; after a longer time the milk becomes rather gray, 



with a slight sediment ; not coagulated or peptonized. Whole milk or 



cream assumes a copper color. 

 Glycerin blood serum (horse). In 6-8 days an orange-colored growth. 



