THE CLASSIFICATION OF BACTERIA 357 



On blood serum and glycerin agar growth softer, flatter, and more watery ; 



also grows more rapidly, i.e. a visible growth in about eight days. 

 Pathogenesis. Highly pathogenic to fowls ; not truly pathogenic to guinea 



pigs, rabbits, and apes. 

 JJabitat. Associated with avian tuberculosis. 



15. Mycobact. smegmatis (Kruse) 



Smegmabacillus Tavel-Alvarez : Bull, de I'Acad. de M6decine, 1885. 

 B. smegmatis Kruse : Fliigge, Die Mikroorganismen, 1896, 517. 



Morphology. Bacilli like Mycobact. syphilidis, but shows a greater variability 

 in size and form. Stain with difficulty, and not decolorized with potassium 

 permanganate, and also retain the stain after long treatment with mineral 

 acids in contradistinction to syphilis, but are easily decolorized with 

 alcohol. For differential diagnosis, stain with hot carbol fuchsin, and 

 immerse in a saturated alcoholic solution of methylene blue, when the 

 smegma bacilli are stained blue and the tubercle bacilli red. 



Habitat. Found on the mucous membranes of the urino-genital tract in man 

 and the lower animals, on the mamma, and in urine. 



16. Mycobact. but3n"i 



Tulerkelahnlicher Bacillus Rabinowitsch : Zeitsch. f. Hygiene, XXVI, 1897, loi. 

 Tuterclehacillen in Butter u. Milch Petri : Arb. a. d. Kais. Gesundheitsamte, XIV, i. 



Morphology. Bacilli identical with tubercle. Stain with carbol fuchsin, and 

 resist decolorization after 4 minutes' immersion in 6 per cent HjSO^. 



Agar colonies. Deep, round — oval, gray, granular. Surface colonies have 

 gray granular centres, and clear crumpled borders, and are often dry and 

 cupped. 



Gelatin stab. Slow growth ; in depth, small disjointed colonies along the line 

 of stab ; medium not liquefied. 



Agar slant. Freshly isolated from the body, the growth is thick, moist, and 

 creamy ; in old cultures, a crumpled membrane, of an orange or copper 

 color. By repeated passage through animals, the cultures on agar or 

 glycerin agar are dry and fragmented or crumpled, closely simulating 

 true tubercle bacilli. 



Totato. A moist gray layer. 



Bouillon and glycerin bouillon. A crumpled membrane on the surface ; media 

 clear. The cultures have an ammoniacal odor, and lack the characteristic 

 yeasty odor of true tubercle cultures. The medium is rendered alkaline. 

 Grow in acid bouillon. Indol is produced. 



