THE CLASSIFICATION OF BACTERIA 129 



VARIETIES 



Often difficult to differentiate from B. coli. Scheffer (Archiv f. Hygiene, 

 XXX, 1897, 291) describes a variety of B. aerogenes which closely con- 

 nects it with B. colt. Diff. . B. coli, when grown anaerobically, showed 

 no change of morphology, while B. aerogenes, grown under the same 

 conditions, developed abnormally long filaments. Guinea pigs immunized, 

 on the one hand against B. aerogenes, and on the other against B. coh, 

 gave sera which possessed diagnostic value ; viz., aerogenes serum 

 caused an agglutination of aerogenes bacilli, but not of B. coli', while 

 coli serum caused an agglutination of B. coli, but not of B. aerogenes. 



Bact. addi-lactici Grotenfelt, Fortschritte Med., VII, 1889, 124. Indistinguish- 

 able from the preceding. 



Habitat. Isolated from faeces, water, milk. 



Bact. a and b Guillebeau: Ann. Micrograph., XI, 225. Indistinguishable 

 from the preceding, except that bacilli show a slight motility. 



Habitat. Isolated from milk. 



21. Bact. capsulatum (Sternberg) 



Capsule Bacillus of Pfeiffer: Zeitsch. f. Hygiene, VI, 1889, 145. 

 Bacillus capsulatus Sternberg: Manual Bacteriology, 1892, 431. 



Morphology. Bacilli thick, with rounded ends, usually 2-3 times their breadth ; 

 often in chains of 2-3 elements, or in filaments. 



Gelatin colonies. Deep : oval, granular. Surface : flat, glistening, porcelain- 

 white. 



Gelatin stab. In depth, a good growth ; on the surface, growth round, glisten- 

 ing, flat, porcelain-white. 



Agar slant. Growth thick, pure white, viscous. 



Potato. Growth moist, glistening, yellowish white, viscid. 



Pathogenesis . Subcutaneous inoculations of mice cause death by septicaemia 

 in 2-3 days. Intraperitoneal inoculations of guinea pigs and pigeons, 

 death in 30 hours ; septicaemia. Rabbits, refractory. 



Habitat. Isolated from the blood of guinea pigs which died spontaneously. 

 According to Strong (Centralblatt f. Bakteriol., XXV, 49), this bacillus 

 generates gas actively in lactose bouillon. 



22. Bact. chinense (Hamilton) 



Bacillus capsulatus-chinensis Hamilton: Centralblatt f. Bakteriol., 2d Abt., IV, 1898, 230. 



Morphology. Bacilli 0.6:4-8 /u, with a capsule. Rods within the capsule 

 small, 0.5-0.7 : 4.0-6.0 //,, with 2-3 elements within a single capsule. In 

 old cultures the rods disintegrate. Decolorized by Gram's method. 





