DESCRIPTION OF SPECIES 



433 



crumb-like scales which coalesce. 

 Blood serum not liquefied. First 

 growth appears lo to 12 days. 



Aerobic. 



Vitality — Considerable, can with- 

 stand desiccation for months ; 

 moist heat at 70° C. for 10 minutes 

 kiUs. 



Pathogenesis — Pathogenic ; pro- 

 duces tuberculosis in man and the 

 lower animals (bovine species of 

 tubercle bacillus) ; very frequent in 

 cows (perlsucht), less frequent in 

 pigs, rare in sheep and horses ; 

 common in birds. 



BACILLUS PSEUDO-TUBER- 

 CULOSIS (Pfeiffer). 



Source and habitat — Isolated from 

 London milks (8 j)er cent.) by 

 Klein. 



Morphology — Resembles B. colt. 

 Short, small bacilli ; cylindrical 

 round ends. 04 to 0-5 m broad 

 1-2 to 1-8 /I long. 



Manner of grouping — Singly, or in 

 couples or chains ; sometimes fila- 

 mentous forms, long chains in 

 bouillon cultm-e ; most noticeable 

 in unstained specimens. 



Staining reaction — Alkaline LofBer's 

 methyl-blue ; 1 5 minutes steaming ; 

 also by Gram's method (Klein). 



Capsule; flagella; motility — Non- 

 motile ; occasionally a terminal 

 flagellum. 



Biology : cultural characters (^includ- 

 ing biochemical features'). 



Bouillon — In 24 hours a well- 

 marked granular cloudiness ; small 

 flocculi float through the liquid ; 

 makes bouillon alkaline. Imper- 

 fect pellicle after several days' 

 growth. No general turbidity. 



Gelatine plates and tubes — 

 Growth resembles B. coli, but the 



colonies are more circumscribed 

 and granular ; later, become 

 tuberculated ; growth slow, and 

 colonies become more opaque, 

 whiter, and less spread out than 

 B. coli. No gas is formed in gela- 

 tine shake cultures. Slight growth 

 in stab-cultiu-e. No liquefection of 

 gelatine. 



Agar plates and tubes — Minute 

 grey-white flat colonies ; thick, less 

 transparent centre. Stroke and 

 stab-cultures similar to B. coli., but 

 not so luxuriant. 



Potato — Limited growth ; faintly 

 brownish ; thin layer with crenated 

 thicker margin of a whitish-yellow 

 colour. 



Milk — Grows well but leaves 

 the milk imaltered ; no curdling. 

 Litmus milk retains its deep-blue 

 colour. 



Blood serum — Grows in colonies 

 similar to the growth on agar ; 

 does not liquefy serum. 



Aerobic. 



Pathogenesis — Guinea - pigs in- 

 oculated subcutaneously with a 

 small quantity of culture die in a 

 few weeks. Their organs are found 

 to be studded with yellow-white 

 nodules containing the bacillus 

 in pure cultm-e. These nodules 

 develop more rapidly than true 

 tuberculosis, but do not contain 

 any giant cells. If fed with food 

 contaminated with this organism 

 similar nodules develop in the 

 walls of the intestine and mesen- 

 teric glands. Klein says : " The 

 presence of the bacillus pseudo 

 tuberculosis in milk may probably 

 play a part in causing pseudo- 

 tuberculous disease in the human 

 subject." He found it present in 

 8 milks out of 100 milks examined 

 in London {Rep. Loc. Gov. Bd.^ 

 1899-1900, pp. 355-384) 

 2 E 



