6i8 



LABORATORY HINTS 



Gram-negative. Do not liquefy gelatine. On gelatin plates form 

 ithin, irregular, notched colonies (see table for dififerentiation). 



(1) The Bacillus coll. 



Short (2 to 4 fi) rounded ends, sometimes almost oval, three to 

 four flagella, feebly motile, no spores. Gram-negative. It never 

 liquefies gelatin, produces permanent acidity in milk which is curdled 

 within seven days at 37° C. Ferments glucose and lactose with acid 

 and gas, forms indol, a thick yellow-brown growth on potato, reduces 

 nitrates. • 



(2) The Capsulated Bacilli. 



Bacillus pneumoniae, or the pneumo-bacillus of Friedlander. 



A short rod (i to 2 /a) with rounded ends, encapsulated, frequently 

 in pairs, non-motile, non-sporing, aerobic and facultative anaerobic. 

 Gram-negative. (The pneumococcus is Gram-positive.) It loses its 

 capsule when cultivated, a nail-shaped growth in stab gelatin, milk 

 slowly coagulated. 



Bacillus lactis aerogenes, non-motile, does not ferment dulcitol, 

 milk rapidly curdled with formation of capsules, forms " nail-head " 

 growth in gelatin. 



(3) The Enteritidis Group. 



The enteritidis group includes such as Gartner's bacillus which 

 causes meat poisoning epidemics. 



The pneumonic group such as bacillus psittacosis causing epidemic 

 pneumonia in parrots and a fatal broncho-pneumonia in man. 



The paratyphoid group causing paratyphoid fever. 



The non-pathogenic group (to man), as the bacillus suicholeras or 

 hog cholera bacillus and the Danysz's bacillus for exterminating rats. 



They all resemble the typhoid bacillus, morphologically being 

 Gram-negative, activelv motile, multi-flagellate, non-sporing, but they 



